LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 


Class 


MODERN  SCIENCE 
READER 


THE  MACMILLAN  COMPANY 

NEW  YORK   •    BOSTON   •    CHICAGO 
SAN  FRANCISCO 

MACMILLAN  &  CO.,  LIMITED 

LONDON  •    BOMBAY  •   CALCUTTA 
MELBOURNE 

THB  MACMILLAN  CO.  OF  CANADA,  LTD. 

TORONTO 


MODERN  SCIENCE 
READER 


WITH   SPECIAL    REFERENCE   TO 


CHEMISTRY 


EDITED  BY 

ROBERT  MONTGOMERY  BIRD,  Ph.,  D. 

ft 

Collegiate  Professor  of  Chemistry  in 
the  University  of  Virginia 


j!2eto  got* 

THE  MACMILLAN  COMPANY 

LONDON:  MACMILLAN  &  CO..  LTD.. 
I9II 

All   right*   rtirn  td 


COPYRIGHT,  1911 
By  THE  MACMILLAN  COMPANY 


Set  up  and  electrotyped.     Published   September,   1911 


Printed  «t 

The  NORWOOD  PRESS 
Berwick  &  Smith  Company,  Norwood,  Massachusetts 


CONTENTS 


PACK 

The  Romance  of  the  Diamond 1 

WILLIAM  CBOOKES 

Making  Money  out  of  Waste 11 

DAY  ALLEN  WILLET 

Modern  Explosives 17 

J.  8.  8.  BRA  ME 

A  Sketch  of  the  History  of  Propellants 28 

ANDREW  NOBLE 

Artificial   Silk. .  ;_. ;......  . V, ... , . . . . ......... ,. -..i .     36 

JOSEPH  CASH 

The  Creators  of  the  Age  of  Steel . . . .^ . *     42 

A  Review 

The  Anatomy  of  a  Steel  Rail 56 

HKXRY  COOK  BOYNTON 

The  Nature  and  Treatment  of  Alloy  Steel 65 

JOHN  A.  MATHEWS 

The  Oxyhydric  Process  of  Cutting  Metals 72 

E.  F.  LAKE 

The  Commercial  Production  of  Oxygen 81 

ALFRED  GRADENWITZ 

Why  a  Flame  Emits  Light 89 

ROBERT  M.  BIRD 

Marvels  of  a  Plant's  Growth  and  the  Chemistry  of 

Decay 103 

VIVIAN  B.  LEWES 

Coal,  Its  Composition  and  Combustion 115 

WILLIAM  H.  BOOTH 


223*057 


vi  CONTENTS 

PAOK 

The  Coal-Tar  Dye  Industry,  Its  Wonderful  Rise  and 

Importance 124 

Natural  and  Artificial  Perfumes 131 

MAX  HEIM 

Scientific  Developments  in  the  Glass  Industry 141 

R.    SCHALLER 

What  Electrochemistry  is  Accomplishing 148 

JOSEPH  W.  RICHARDS 

The  Yeast  Cell  and  its  Lessons 169 

W.  STANLEY  SMITH 

The  Chemical  Regulation  of  the  Processes  of  the  Body  181 
WILLIAM  HENRY  HOWELL 

The  Science  of  Chemistry  and  its  Development 195 

Selections  from  The  New  International  Encyclopaedia 

The  Age  of  Science 230 

IRA  REMSEN 

The  Old  and  the  New  Alchemy 245 

HERMANN  KOPP 

Radioactivity   270 

MADAME  CURIE 

Visible  Molecules,  Corpuscles  and  Ions. .  .  279 


The  Electronic  Theory  of  Matter 286 

OLIVER  LODGE 

The  Ether  of  Space 290 

OLIVER  LODGE 

Unsolved  Problems  of  Chemistry 305 

IRA  REMSEN 

Regarding  Additional  Reading 322 

THE  EDITOR 


PREFACE 

Tins  book  provides  a  partial  course  of  reading  in  Chem- 
ist ry  for  college  men  and  general  readers,  and  indicates 
further  matter  of  an  interesting  and  instructive  nature. 
It  is  the  first  volume  of  a  series  of  Readers  which  will  con- 
tain reprints  of  modern  papers  and  addresses,  gathered 
from  many  sources  and  edited  to  suit  the  purposes  herein 
explained. 

It  is  our  experience  with  college  men  that  parallel  read- 
ing, more  than  any  other  influence,  conduces  to  interest  in 
text-book  matter,  especially  in  first-year  courses  in  science. 
It  broadens  the  student's  views,  enlivens  the  subject  and 
shows  its  bearing  upon  the  work  and  problems  of  life.  We 
believe  that  some  reading  of  good  scientific  literature  in 
each  distinct  branch  of  Natural  Science  should  be  required 
of  every  undergraduate;  this  volume  attempts  to  supply 
suitable  matter  for  Chemistry.  \Ve  seek  to  help  teachers 
to  introduce  such  literature  and  its  authors  to  college  stu- 
dents, and  to  acquaint  students  with  the  more  easily  avail- 
able sources  of  reliable  articles  of  a  popular  nature.  It  is 
hoped  that  these  readers  will  be  of  special  service  to  teach- 
ers of  large  classes,  where  the  inspiration  of  personal  con- 
tact is  necessarily  small;  and  also  that  they  will  help  to 
awaken  interest  in  science  among  those  who  think  they 
have  no  aptitude  for  such  branches  of  knowledge. 

We  have  had  in  mind,  also,  persons  who  are  seeking 
knowledge  without  the  aid  of  a  teacher.  Definite  infor- 
mation for  reading  and  home  study  is  given,  such  as  the 
editor  now  wishes  he  had  known  how  to  obtain  while  in 
business,  before  going  to  college  or  expecting  ever  to  have 
the  time  to  do  so.  We  wish  to  increase  the  service  of 
popular  science  by  aiding  readers  of  such  to  find  good 
matter.  We  do  this  because  we  believe  that  the  widespread 

vii 


viii  PREFACE 

habit  of  reading  the  scientific  contributions  to  magazines 
and  newspapers  is  responsible  in  no  small  measure  for  the 
present-day  quick  acceptance  of  applications  of  pure  re- 
search, and  that  it  has  also  contributed  greatly  to  the 
development  of  workers  who  apply  the  discoveries  of 
science,  and  of  business  men  who  promote  such  applications. 
We  have  selected  articles  which  will  whet  the  taste  for 
knowledge  without  giving  rise  to  unbalanced  and  unscien- 
tific ideas;  which  will  contribute  to  contemplative  habits 
of  reading,  and  thereby  help  to  develop  that  culture, 
efficiency,  and  capacity  for  productive  thinking  which  wins 
success  in  any  field.  We  have  endeavored,  particularly, 
to  choose  articles  which  are  suggestive,  which  will  broaden 
the  reader's  outlook  on  science  by  showing  him  the  interre- 
lations of  its  different  branches,  and  which  will  impress 
upon  him  the  advantage  such  a  broad  view  gives  in  the 
solution  of  the  problems  of  the  business  and  professional 
man.  The  papers  contain  the  information  which  permits 
them  to  be  readily  understood;  they  are  popular  in  style, 
that  is,  they  possess  ' '  human  interest, ' '  and  some  have  even 
a  "once-upon-a-time"  flavor;  yet  they  are  all  of  a  scientific 
and  dignified  character. 

We  wish  to  express  our  thanks  to  the  authors  and  original 
publishers  for  permission  to  republish  the  articles;  like- 
wise to  the  publishers  of  the  New  International  Encyclo- 
paedia, for  permission  to  include  some  of  the  excellent 
chemical  articles  contained  therein.  We  shall  feel  under 
obligations  to  any  one  who  calls  our  attention  to  suitable 
papers  not  now  included. 

Later  volumes  will  be  devoted  to  other  branches  of 
science,  and  a  bibliographical  volume  will  contain  interest- 
ing and  inspiring  sketches  of  the  lives  and  work  of  some 
of  the  men  who  have  either  added  to  the  stock  of  human 
knowledge  or  who  have  applied  it  to  human  needs. 

R.  M.  BIRD. 

University  of  Virginia, 
January,  1911. 


THE  ROMANCE  OF  THE  DIAMOND1 

BY  SIR  WILLIAM  CROOKES,  D.  Sc.,  F.  R.  S. 

FROM  the  earliest  times,  the  diamond  has  fascinated  man- 
kind. It  has  been  a  perennial  puzzle— one  of  the  "riddles 
of  the  painful  earth. "  Speculations  as  to  the  probable 
origin  of  the  diamond  have  been  greatly  forwarded  by 
patient  research,  and  particularly  by  improved  means  of 
obtaining  high  temperatures,  an  advance  we  owe  prin- 
cipally to  the  researches  of  Professor  Moissan. 

There  is  one  theory  of  the  origin  of  diamonds  which 
appeals  to  the  fancy.  It  is  said  that  the  diamond  is  a  gift 
from  Heaven,  conveyed  to  earth  in  meteoric  showers.  The 
suggestion,  I  believe,  was  first  broached  by  A.  Meydendauer, 
who  said : 

The  diamond  can  only  be  of  cosmic  origin,  having  fallen  as  a 
meteorite  at  later  periods  of  the  earth's  formation.  The  available 
localities  of  the  diamond  contain  the  residues  of  not  very  compact 
meteoric  masses,  which  may,  perhaps,  have  fallen  in  prehistoric 
ages,  and  which  have  penetrated  more  or  less  deeply,  according  to 
the  more  or  less  resistant  character  of  the  surface  where  they  fell. 
Their  remains  are  crumbling  away  on  exposure  to  the  air  and  sun, 
and  the  rain  has  long  ago  washed  away  all  prominent  masses.  The 
enclosed  diamonds  have  remained  scattered  in  the  river-beds,  while 
the  fine,  light  matrix  has  been  swept  away. 

According  to  this  hypothesis,  the  so-called  volcanic  pipes 
peculiar  to  all  diamond  mines  are  simply  holes  bored  in  the 
solid  earth  by  the  impact  of  monstrous  meteors — the  larger 
masses  boring  the  holes,  while  the  smaller  masses,  disinte- 
grating in  their  fall,  distributed  diamonds  broadcast. 

Bizarre  as  such  a  theory  appears,  I  am  bound  to  admit 

1  Published    in    yorth   American  Revirw,   March,    1908. 
1  1 


1  ^MObE^k  SCIENCE  READER 

that  there  are  many  circumstances  which  show  that  the 
notion  of  the  heavens  raining  diamonds  is  not  impossible. 
The  most  striking  confirmation  of  the  meteoric  theory 
comes  from  Arizona.  Here,  on  a  broad  open  plain,  over 
an  area  about  five  miles  in  diameter,  have  been  scattered 
one  or  two  thousand  masses  of  metallic  iron,  the  fragments 
varying  in  weight  from  half  a  ton  to  a  fraction  of  an 
ounce.  There  is  little  doubt  that  these  masses  formed  part 
of  a  meteoric  shower,  although  no  record  exists  as  to  when 
the  fall  took  place. 

Curiously  enough,  near  the  center,  where  most  of  the 
meteorites  have  been  found,  is  a  crater  with  raised  edges 
three  quarters  of  a  mile  in  diameter  and  about  six  hundred 
feet  deep,  bearing  exactly  the  appearance  which  would  be 
produced  had  a  mighty  mass  of  iron  struck  the  ground  and 
buried  itself  deep  under  the  surface.  Altogether,  ten  tons 
of  this  iron  have  been  collected  and  specimens  of  the  Caiion 
Diablo  meteorite  are  in  most  collectors  *  cabinets. 

An  ardent  mineralogist,  the  late  Dr.  Foote,  cutting  a 
section  of  this  meteorite,  found  the  tools  were  injured  by 
something  vastly  harder  than  metallic  iron.  He  examined 
the  specimen  chemically,  and  soon  after  announced  to  the 
scientific  world  that  the  Canon  Diablo  meteorite  contained 
black  and  transparent  diamonds.  This  startling  discovery 
was  afterward  verified  by  Professors  Moissan  and  Freidel ; 
and  Moissan,  working  on  a  piece  of  the  Canon  Diablo 
meteorite,  has  recently  found  smooth  black  diamonds  and 
transparent  diamonds,  in  the  form  of  octahedra  with 
rounded  edges,  together  with  green  hexagonal  crystals  of 
carbon  silicide.  The  presence  of  carbon  silicide  in  the 
meteorite  shows  that  it  must,  at  some  time,  have  experienced 
the  temperature  of  the  electric  furnace. 

Under  atmospheric  influences  the  iron  would  rapidly 
oxidize  and  rust  away,  and  the  meteoric  diamonds  would 
be  unaffected  and  left  on  the  surface  of  the  soil,  to  be 
found  haphazard  when  oxidation  had  removed  the  last 
proof  of  their  celestial  origin.  That  there  are  still  lumps 


THE  ROMANCE  OP  THE  DIAMOND  3 

of  iron  left  in  Arizona  is  merely  due  to  the  extreme  dry- 
ness  of  the  climate  and  the  comparatively  short  time  the 
iron  has  been  on  our  planet.  We  are  witnesses  to  the 
course  of  an  event  which  may  have  happened  in  geologic 
times  anywhere  on  the  earth's  surface. 

Although  in  Arizona  diamonds  have  fallen  from  the 
skies,  confounding  our  senses,  this  descent  of  precious 
stones  is  what  may  be  called  a  freak  of  nature  rather  than 
a  normal  occurrence.  To  the  average  reader  it  is  now 
known  that  there  is  no  great  difference  between  the  compo- 
sition of  our  earth  and  that  of  extraterrestrial  masses. 
The  mineral  peridot  is  present  in  most  meteorites.  Yet 
no  one  doubts  that  peridot  is  also  a  true  constituent  of 
rocks  formed  on  this  earth.  The  spectroscope  reveals  that 
the  elementary  composition  of  the  stars  and  the  earth  are 
pretty  much  the  same.  The  spectroscope  also  shows  that 
meteorites  have  as  much  of  earth  as  of  heaven  in  their 
composition.  Indeed,  not  only  are  the  selfsame  elements 
present  in  meteorites,  but  they  are  combined  in  the  same 
way  to  form  the  same  minerals  as  in  the  crust  of  the  earth. 

It  is  certain  from  observations  I  have  made,  corroborated 
by  experience  gained  in  the  laboratory,  that  iron  at  a  high 
temperature  and  under  great  pressure— conditions  existent 
at  great  depths  below  the  surface  of  the  earth— acts  as  the 
long-sought  solvent  for  carbon,  and  will  allow  it  to  crystal- 
lize out  in  the  form  of  diamond.  But  it  is  also  certain, 
from  the  evidence  afforded  by  the  Arizona  and  other 
meteorites,  that  similar  conditions  have  existed  among 
bodies  in  space,  and  that  on  more  than  one  occasion  a 
meteorite  freighted  with  jewels  has  fallen  as  a  star  from 
the  sky. 

Many  circumstances  point  to  the  conclusion  that  the  dia- 
mond of  the  chemist  and  the  diamond  of  the  mine  are 
strangely  akin  as  to  origin.  It  is  evident  that  the  diamond 
has  not  been  formed  in  situ  in  the  blue  ground  where  it  is 
found.  The  genesis  must  have  taken  place  at  vast  depths 
under  enormous  pressure.  The  explosion  of  large  diamonds 


4  MODERN  SCIENCE  READER 

on  coming  to  the  surface  shows  extreme  tension.  More 
diamonds  are  found  in  fragments  and  splinters  than  in 
perfect  crystals;  and  it  is  noteworthy  that,  although  these 
splinters  and  fragments  must  be  derived  from  the  breaking 
up  of  a  large  crystal,  yet  in  only  one  instance  have  pieces 
been  found  which  could  be  fitted  together;  and  these 
occurred  at  different  levels.  Does  not  this  fact  point  to 
the  conclusion  that  the  blue  ground  is  not  their  true  matrix  ? 
Nature  does  not  make  fragments  of  crystals.  As  the  edges 
of  the  crystals  are  still  sharp  and  unabraded,  the  locus  of 
formation  cannot  have  been  very  distant  from  the  present 
sites.  There  were  probably  many  sites  of  crystallization 
differing  in  place  and  time,  or  we  should  not  see  such  dis- 
tinctive characters  in  the  gems  from  different  mines,  nor 
indeed  in  diamonds  from  different  parts  of  the  same  mine. 

Although  my  experiments  are  chiefly  connected  with  the 
physical  and  chemical  properties  of  diamonds,  and  with 
researches  on  the  perplexities  of  their  probable  formation, 
it  will  be  a  kind  of  compensation  for  some  of  my  theories 
if  I  bring  before  the  reader  the  general  character  of  the 
South  African  diamond  mines  and  their  surroundings. 

The  most  famous  diamond  mines  in  the  world  are  Kim- 
berley,  De  Beers,  Dutoitspan,  Bulfontein  and  Wesselton. 
Kimberley  is  practically  in  the  center  of  the  present 
diamond-producing  area.  The  five  diamond  mines  are  all 
contained  in  a  precious  circle  three  and  one  half  miles  in 
diameter.  They  are  irregular-shaped  round  or  oval  pipes, 
extending  vertically  downward  to  unknown  depths  and 
becoming  narrower  as  the  depth  increases.  They  are  con- 
sidered to  be  volcanic  necks  filled  from  below  with  a  hetero- 
geneous mixture  of  fragments  of  surrounding  rocks,  and  of 
older  rocks,  such  as  granite,  mingled  and  cemented  with  a 
bluish-colored  hard  mass,  in  which  famous  "blue  ground " 
the  imbedded  diamonds  are  hidden. 

How  the  great  pipes  were  originally  formed  it  is  hard  to 
say.  They  were  certainly  not  burst  through  in  the  ordinary 
manner  of  volcanic  eruption,  since  the  surrounding  and 


THE  ROMANCE  OF  THE  DIAMOND  5 

enclosing  walls  show  no  signs  of  igneous  action,  and  are  not 
shattered  or  broken  up  even  when  touching  the  "blue 
ground."  It  is  pretty  certain  that  these  pipes  were  filled 
from  below  after  they  were  pierced,  and  the  diamonds 
were  formed  at  some  previous  time  and  mixed  with  a  mud 
volcano,  together  with  all  kinds  of  debris  eroded  from  the 
rocks  through  which  it  erupted,  forming  a  geological  '  '  plum 
pudding. "  A  more  wildly  heterogeneous  mixture  can 
hardly  be  found  anywhere  else  on  this  globe. 

It  may  be  that  each  volcanic  pipe  is  the  vent  for  its  own 
laboratory— a  laboratory  buried  at  vastly  greater  depths 
than  we  have  yet  reached— where  the  temperature  is  com- 
parable with  that  of  the  electric  furnace,  where  the  pres- 
sure is  fiercer  than  in  our  puny  laboratories  and  the 
melting-point  higher,  where  no  oxygen  is  present,  and 
where  masses  of  liquid  carbon  have  taken  centuries,  per- 
haps thousands  of  years,  to  cool  to  the  solidifying-point. 

In  1903  the  Kimberley  mine  had  reached  a  depth  of 
2,599  feet.  Tunnels  are  driven  from  the  various  shafts  at 
different  levels,  about  120  feet  apart,  to  cross  the  mine  from 
west  to  east.  These  tunnels  are  connected  by  two  other 
tunnels  running  north  and  south.  The  scene  belowground 
in  the  labyrinth  of  galleries  is  bewildering  in  its  complexity, 
and  very  unlike  the  popular  notion  of  a  diamond  mine. 
All  below  is  dirt,  mud,  grime ;  half -naked  men  dark  as 
mahogany,  lithe  as  athletes,  dripping  with  perspiration, 
are  seen  in  every  direction,  hammering,  picking,  shovelling, 
wheeling  the  trucks  to  and  fro,  keeping  up  a  weird  chant 
which  rises  in  force  and  rhythm  when  a  greater  task  calls 
for  excessive  muscular  strain.  The  whole  scene  is  more 
suggestive  of  a  coal  mine  than  of  a  diamond  mine,  and  all 
this  mighty  organization— this  strenuous  expenditure  of 
energy,  this  costly  machinery,  this  ceaseless  toil  of  skilled 
and  black  labor— goes  on  day  and  night,  just  to  win  a  few 
stones  wherewith  to  deck  my  lady 's  finger !  All  to  gratify 
the  vanity  of  woman!  "And,"  I  hear  my  fair  reader 
remark,  '  *  the  depravity  of  man ! '  * 


6  MODERN  SCIENCE  READER 

Prodigious  diamonds  are  not  so  uncommon  as  is  generally 
supposed.  Diamonds  weighing  over  an  ounce  (151.5 
carats)  are  not  infrequent  at  Kimberley.  I  have  seen  in 
one  parcel  of  stones  eight  perfect  ounce  crystals,  and  one 
inestimable  stone  weighing  two  ounces.  The  largest  known 
diamond,  the  "Cullinan,"  was  found  in  the  New  Premier 
Mine.  It  weighs  no  less  than  3,025  carats,  or  1.37  pounds 
avoirdupois.  It  is  a  fragment,  probably  less  than  half,  of 
a  distorted  octahedral  crystal.  The  other  portions  still 
await  discovery  by  some  fortunate  miner. 

At  the  close  of  the  year  1904,  ten  tons  of  diamonds  had 
come  from  these  mines,  valued  at  $300,000,000.  This  mass 
of  blazing  gems  could  be  accommodated  in  a  box  five  feet 
square  and  six  feet  high.  The  diamond  has  a  peculiar 
luster,  and  on  the  sorter's  table  it  is  impossible  to  mistake 
it  for  any  other  stone.  It  looks  somewhat  like  clear  gum 
arabic.  From  the  sorting-room  the  stones  are  taken  to  the 
Diamond  Office  to  be  cleaned  in  acids  and  sorted  into  classes 
by  the  valuators,  according  to  color  and  purity.  It  is  a 
sight  for  Aladdin  to  behold  the  sorters  at  work.  In  the 
Kimberley  treasure  store  the  tables  are  literally  heaped 
with  stones  won  from  the  rough  blue  ground— stones  of  all 
sizes,  purified,  flashing  and  of  inestimable  price;  stones 
coveted  by  men  and  women  all  the  world  over. 

Where  fabulous  riches  are  concentrated  into  so  small  a 
bulk,  it  is  not  surprising  that  precautions  against  robbery 
are  elaborate.  The  Illicit  Diamond-Buying  Laws  are  very 
stringent;  and  the  searching,  rendered  easy  by  the  " com- 
pounding "  of  the  natives,  is  of  the  most  drastic  character. 
The  value  of  stolen  diamonds  at  one  time  reached  nearly 
$5,000,000  a  year.  Now  the  safeguard  against  this  is  the 
"compound."  This  is  a  large  square,  about  twenty  acres, 
surrounded  by  rows  of  one-story  buildings,  divided  into 
rooms  holding  about  twenty  natives  each. 

Within  the  enclosure  is  a  store  where  the  necessaries  of 
life  are  supplied  at  a  reduced  price,  and  wood  and  water 
free.  In  the  middle  is  a  large  swimming-bath  with  fresh 


THE  ROMANCE  OF  THE  DIAMOND  7 

water  running  through  it.  The  rest  of  the  space  is  devoted 
to  games,  dances,  concerts  and  any  other  amusement  the 
native  mind  can  desire.  In  the  compound  are  to  be  seen 
representatives  of  nearly  all  the  picked  types  of  African 
tribes.  The  clothing  in  the  compound  is  diverse  and  orig- 
inal. Some  of  the  men  are  evident  dandies,  whilst  others 
think  that  in  so  hot  a  climate  a  bright-colored  handkerchief 
or  "a  pair  of  spectacles  and  a  smile*'  is  as  great  a  compli- 
ance with  the  requirements  of  civilization  as  can  be 
expected. 

One  Sunday  afternoon,  my  wife  and  I  walked  unattended 
about  the  compound,  almost  the  only  whites  present  among 
1,700  natives.  At  one  part  a  Kaffir  was  making  a  pair  of 
trousers  with  a  bright  nickel-plated  sewing-machine,  in 
which  he  had  invested  his  savings.  Next  to  him,  a  "boy" 
was  reading  from  the  Testament  in  his  own  language  to  an 
attentive  audience.  In  a  corner,  a  party  were  engaged  in 
cooking  a  savory  mess  in  an  iron  pot ;  and,  further  on,  the 
orchestra  was  tuning  up,  and  Zulus  were  putting  the 
finishing  touches  to  their  toilet  of  feathers  and  beads.  One 
group  was  intently  watching  a  mysterious  game.  It  is 
played  by  two  sides,  with  stones  and  grooves  and  hollows 
in  the  ground,  and  appears  to  be  of  most  absorbing  interest. 
It  seems  to  be  universal  throughout  Africa ;  it  is  met  with 
among  the  ruins  of  Zimbabwe,  and  signs  of  it  are  recorded 
on  old  Egyptian  monuments. 

A  word  as  to  the  hardness  of  diamonds.  They  vary 
much  in  this  respect;  even  different  parts  of  the  same 
crystal  differ  in  their  resistance  to  cutting  and  grinding. 
So  hard  is  diamond  in  comparison  to  glass  that  a  suitable 
splinter  of  diamond  will  plane  curls  of?  a  glass  plate  as  a 
carpenter's  tool  will  plane  shavings  off  a  deal  board. 
Another  experiment  that  will  illustrate  its  hardness  is  to 
place  a  diamond  on  the  flattened  end  of  a  conical  block  of 
steel,  and  upon  it  bring  another  similar  cone  of  steel.  If 
I  force  them  together  with  hydraulic  power  I  can  force  the 
stone  into  the  steel  blocks  without  injuring  the  diamond 


8  MODERN  SCIENCE  READER 

in  the  least.  The  pressure  which  I  have  brought  to  bear 
in  this  experiment  has  been  equal  to  170  tons  per  square 
inch  of  diamond. 

The  only  serious  rival  of  the  diamond  in  hardness  is  the 
metal  tantalum.  In  an  attempt  to  bore  a  hole  through  a 
plate  of  this  metal,  a  diamond  drill  was  used  revolving  at 
the  rate  of  5,000  revolutions  per  minute.  This  whirling 
force  was  continued  ceaselessly  for  three  days  and  nights, 
when  it  was  found  that  only  a  small  point,  one  fourth  of  a 
millimeter  deep,  had  been  drilled,  and  it  was  a  moot  point 
which  had  suffered  most  damage,  the  diamond  or  the 
tantalum. 

After  exposure  for  some  time  to  the  sun,  many  diamonds 
glow  in  a  dark  room.  One  beautiful  green  diamond  in  my 
collection,  when  phosphorescing  in  a  vacuum,  gives  almost 
as  much  light  as  a  candle,  and  you  can  easily  read  by  its 
rays.  But  the  time  has  hardly  come  when  we  can  use  dia- 
monds as  domestic  illuminants!  Mrs.  Kunz,  wife  of  the 
well-known  New  York  mineralogist,  possesses  perhaps  the 
most  remarkable  of  all  phosphorescing  diamonds.  This 
prodigy  diamond  will  phosphoresce  in  the  dark  for  some 
minutes  after  being  exposed  to  a  small  pocket  electric  light, 
and  if  rubbed  on  a  piece  of  cloth  a  long  streak  of  phos- 
phorescence appears. 

For  the  manufacture  of  a  diamond,  the  first  necessity  is 
to  select  pure  iron— free  from  sulphur,  silicon,  phosphorus, 
and  so  forth— and  to  pack  it  in  a  carbon  crucible  with  pure 
charcoal  from  sugar.  The  crucible  is  then  put  into  the 
body  of  the  electric  furnace,  and  a  powerful  arc  formed 
close  above  it  between  carbon  poles,  utilizing  a  current  of 
700  amperes  at  40  volts  pressure.  The  iron  rapidly  melts 
and  saturates  itself  with  carbon.  After  a  few  minutes' 
heating  to  a  temperature  above  4,000°  C.— a  temperature 
at  which  the  iron  melts  like  wax  and  volatilizes  in  clouds— 
the  current  is  stopped,  and  the  dazzling  fiery  crucible  is 
plunged  beneath  the  surface  of  cold  water,  where  it  is  held 
till  it  sinks  below  a  red  heat. 


THE  ROMANCE  OP  THE  DIAMOND  9 

As  is  well  known,  iron  increases  in  volume  at  the  moment 
of  passing  from  the  liquid  to  the  solid  state.  The  sudden 
cool  ing  solidifies  the  outer  layer  of  iron  and  holds  the  inner 
molten  mass  in  a  tight  grip.  The  expansion  of  the  inner 
liquid  on  solidifying  produces  an  enormous  pressure,  and 
under  the  stress  of  this  pressure  the  dissolved  carbon 
separates  out  in  transparent  forms— minutely  microscopic, 
it  is  true— but  all  the  same  veritable  diamonds,  with  crystal- 
line form  and  appearance,  color,  hardness  and  action  on 
light  the  same  as  the  natural  gem. 

Now  commences  the  tedious  part  of  the  process.  The 
metallic  ingot  is  attacked  with  hot  nitro-hydrochloric  acid 
until  no  more  iron  is  dissolved.  The  bulky  residue  con- 
sists chiefly  of  graphite,  together  with  translucent  chest- 
nut-colored flakes  of  carbon,  black  opaque  carbon  as 
hard  as  diamonds— black  diamonds,  in  fact— and  a  small 
portion  of  transparent  colorless  diamonds  showing  crystal- 
line structure. 

The  residue  is  first  heated  for  some  hours  with  strong 
sulphuric  acid  at  the  boiling-point,  with  the  cautious  addi- 
tion of  powdered  nitre.  It  is  then  well  washed,  and  for 
two  days  allowed  to  soak  in  strong  hydrofluoric  acid  in 
cold,  then  in  boiling,  acid.  After  this  treatment  the  soft 
graphite  disappears,  and  most,  if  not  all,  the  silicon  com- 
pounds have  been  destroyed. 

Hot  sulphuric  acid  is  again  applied  to  destroy  the  flu- 
orides; and  the  residue,  well  washed,  is  attacked  with  a 
mixture  of  the  strongest  nitric  acid  and  powdered  potas- 
sium chlorate,  kept  warm— but  not  above  60°  C.,  to  avoid 
explosions.  This  treatment  must  be  repeated  six  or  eight 
times,  when  all  the  hard  graphite  will  gradually  be  dis- 
solved, and  little  else  left  but  graphitic  oxid,  diamond  and 
the  harder  carbonado  or  black  diamond  and  boart.  The 
residue  is  fused  for  an  hour  in  fluorhydrate  of  fluorid  of 
potassium,  then  boiled  out  in  water,  and  again  heated  in 
sulphuric  acid. 

The  well-washed  grains  which  resist  this  energetic  treat- 


10  MODERN  SCIENCE  READEK 

ment  are  dried,  carefully  deposited  on  a  slide  and  examined 
under  the  microscope.  Although  many  fragments  of 
crystals  occur,  it  is  remarkable  I  have  never  seen  a  complete 
crystal.  All  appear  shattered,  as  if  on  being  liberated 
from  the  intense  pressure  under  which  they  were  formed 
they  burst  asunder.  I  have  singular  evidence  of  this 
phenomenon.  A  fine  piece  of  artificial  diamond,  carefully 
mounted  by  me  on  a  microscopic  slide,  exploded  during 
the  night  and  covered  the  slide  with  fragments.  This 
bursting  paroxysm  is  not  unknown  at  the  Kimberley 
diamond  mines. 


MAKING  MONEY  OUT  OF  WASTE1 

BY  DAY  ALLEN  WILLEY 

ONE  of  the  most  interesting  phases  of  the  world 's  develop- 
ment is  the  manner  in  which  the  people  of  civilized  nations 
are  utilizing  so  many  things  which  were  only  recently  con- 
sidered as  valueless— to  be  thrown  away  as  worthless; 
while  what  we  have  thought  was  useless  stuff,  merely  fit  to 
be  trod  under  the  feet  as  so  much  dirt,  has  been  converted 
into  a  product  of  great  value.  The  increase  in  the  popula- 
tion of  various  countries,  and  especially  the  increase  in  the 
number  of  inhabitants  of  great  cities,  has  been  one  of  the 
reasons  why  the  genius  of  the  inventor  has  contrived  to 
make  what  we  have  called  waste  of  worth  to  us  by  using  it 
in  various  compounds  and  articles  which  have  already  be- 
come indispensable.  The  things  that  are  thrown  into  the 
street,  house-yard,  and  other  receptacles  for  debris  can  be 
used  in  so  many  ways,  that  scarcely  anything  can  now  be 
considered  refuse.  For  instance,  old  tin  cans  are  melted 
to  be  molded  into  buttons,  covers  for  luggage,  and  toys  for 
children,  which  sell  throughout  the  world  at  Christmas 
time.  Discarded  shoes  and  rubbers,  also  scraps  of  leather, 
have  become  of  value  in  manufacturing  various  substances. 
Not  a  single  bottle  or  other  piece  of  glass  need  be  thrown 
away,  for  mixed  with  certain  kinds  of  earth  and  sand,  it 
makes  an  excellent  artificial  stone  for  buildings.  Not  so 
long  ago  dead  animals  were  buried,  as  it  was  not  known 
that  their  bones,  hide,  and  even  parts  of  the  intestines  were 
of  use.  Much  of  the  inflammable  composition  in  the  lucifer 
match  is  now  obtained  from  such  bones.  Even  the  sweep- 
ings of  the  street  pavement,  containing  as  they  do  particles 
of  horseshoes  and  other  metal,  are  worth  gathering;  while 
1  Scientific  American  Supplement,  April  10,  1910. 
11 


12  MODERN  SCIENCE  READER 

the  bits  which  fall  from  the  horse's  hoof  as  it  is  being  shod 
by  the  farrier  make  a  most  valuable  dye  when  mixed  with 
certain  chemicals  and  metal  scraps. 

Over  nearly  every  large  city,  especially  such  centers  as 
London,  Birmingham,  and  seats  of  other  great  countries, 
are  enormous  clouds  of  smoke,  which  so  frequently  darken 
the  atmosphere  that  even  at  noontime  it  is  necessary  to  have 
lights  in  the  buildings.  Yet  this  smoke  if  properly  treated 
can  be  actually  dissolved  into  several  most  useful  elements 
—and  the  inventor  has  designed  apparatus  by  which  these 
elements  can  be  secured  at  a  small  cost.  It  is  a  fact  that 
smoke  can  be  weighed  and  measured  like  so  much  earth 
and  sand.  Experiments  which  have  been  made  in  the 
United  States  show  that  a  cord  of  ordinary  fuel  wood  in 
burning  generates  28,000  cubic  feet  of  smoke.  If  the 
smoke  from  one  hundred  cords  of  wood  is  treated  by  this 
process,  it  will  yield  no  less  than  six  tons  of  the  valuable 
chemical  known  as  acetate  of  lime,  besides  twenty-five 
pounds  of  tar.  But  the  smoke  contains  so  much  of  the 
elements  of  alcohol,  that  this  quantity  will  produce  no  less 
than  two  hundred  gallons  of  spirit  suitable  for  lighting, 
heating,  or  the  operation  of  motors. 

Usually  perfumes  and  other  useful  odors  are  considered 
as  being  obtained  principally  from  flowers.  The  oils  com- 
ing from  waste  fruit,  such  as  decayed  pears,  grapes,  and 
peaches,  however,  can  be  substituted  for  some  of  the  most 
costly  floral  odors  after  being  treated  with  acids  and  other 
liquids  which  give  them  a  remarkable  fragrance.  Perfume, 
soaps,  even  confectionery,  are  now  manufactured,  which  are 
flavored  with  what  is  called  the  oil  of  bitter  almonds,  but 
which  is  extracted  from  the  tar  which  is  a  refuse  of  gas- 
making  plants  such  as  are  to  be  found  in  every  large  city. 

The  enormous  production  of  iron  and  steel  in  various 
forms  has  caused  great  furnaces  to  be  erected  for  smelting 
this  metal  in  large  quantities.  Here  again  a  study  has  been 
made  of  what  can  be  done  to  use  what  was  formerly  waste. 
Even  the  gas  which  in  the  past  has  been  allowed  to  escape 


MAKING  MONEY  OUT  OF  WASTE  13 

in  the  air  has  been  made  prisoner,  so  to  speak,  and  converted 
into  a  most  valuable  factor.  The  mixture  left  after  the 
iron  has  been  extracted  from  the  ore — sometimes  called  slag 
—which  represents  the  debris  of  the  iron  ore,  is  now  one  of 
the  most  valuable  compounds  coming  from  the  blast  fur- 
nace, although  but  a  few  years  ago  it  was  thrown  away.  In 
fact,  blast  furnaces  have  been  built  on  the  edge  of  swamps 
and  bodies  of  water,  so  that  the  slag  could  be  thrown  into 
these  places  and  used  for  filling  them  up.  Very  good  glass 
is  now  made  from  this  slag,  as  well  as  paving  blocks  and 
bricks,  artificial  porphyry,  and  a  cement  which  is  equal  to 
the  best.  Ground  with  six  per  cent,  of  slaked  lime,  build- 
ing mortar  is  also  made  from  slag ;  and  ornamental  copings 
and  moldings,  window  sills,  and  chimney  pieces  are  fash- 
ioned of  it. 

Slag  brick  is  stated  to  be  quite  as  strong  as  ordinary 
brick,  and  much  less  permeable  to  moisture.  To  make  1,000 
brick,  6,000  or  7,000  pounds  of  granulated  slag,  and  from 
500  to  700  pounds  of  burned  lime,  are  consumed.  Good 
bricks  also  can  be  made  from  granulated  slag  mixed  with 
dust  from  slag,  though  the  hardening  process  is  rather  slow. 
Slag  is  also  used  for  steampipe  and  boiler  wrappings,  in 
which  form  it  is  called  "silicate  of  cotton."  Coal  slag  is 
a  good  structural  material  when  mixed  with  slaked  lime. 
Basic  slag  is  used  in  large  quantities  by  manufacturers  of 
fertilizers,  instead  of  phosphate  rock. 

The  greatest  metal  industry  in  the  world,  which  is  now 
being  built  in  Indiana,  forming  an  entire  city  in  itself,  is 
provided  with  iron  smelters  from  which  the  gas  as  it  rises 
will  be  returned  to  the  fires  beneath  the  ore  and  used  for 
heat.  By  this  system  the  cost  of  coal  to  smelt  the  ore  will 
be  about  one  half  the  expense  if  the  gas  were  not  secured 
as  stated.  Waste  gas  has  been  utilized  by  inventors  for  the 
direct  operation  of  engines  so  large  that  they  have  a  force 
equal  to  the  power  of  a  thousand  horses.  As  it  issues  from 
the  smelter,  the  gas  enters  a  large  cover,  as  it  might  be 
termed,  placed  above  the  furnace.  In  the  center  of  the 


14  MODERN  SCIENCE  READER 

cover  is  a  pipe,  through  which  the  gas  passes  into  a  reser- 
voir below.  From  this  it  is  forced  directly  into  the  engine, 
and  ignited  by  an  electric  spark.  This  causes  it  to  explode, 
and  the  force  of  the  explosion  drives  the  engines  and  the 
other  machinery. 

One  of  the  most  important  discoveries  which  has  been 
made  in  connection  with  what  we  have  called  waste  products 
is  the  value  of  sawdust.  Usually  sawmills  produce  such 
large  quantities  of  the  material,  that  it  cannot  be  burned 
to  advantage.  It  is  then  thrown  away,  so  to  speak,  some- 
times being  piled  in  great  heaps  and  left  to  slowly  consume. 
A  very  good  quality  of  alcohol,  however,  can  be  distilled 
from  ordinary  sawdust  by  an  inexpensive  process,  in  such 
quantities  that  two  gallons  of  the  liquid  can  be  obtained 
from  220  pounds  of  dust.  The  sawdust  from  birch  and 
some  other  species  of  forest  trees  will  also  yield  a  palatable 
sugar  after  it  has  been  treated  with  certain  chemicals.  In 
America  and  in  some  parts  of  Europe  an  enormous  quantity 
of  the  dust  is  sold,  being  vended  about  in  wagons  and  in 
sacks  carried  on  the  backs  of  the  venders.  It  is  bought  to 
sprinkle  on  the  floors  of  cafes,  butcher  shops,  and  other 
places  where  it  will  prevent  dirt  from  sticking  to  the  floors. 
In  recent  years  so  many  dolls  and  other  "stuffed"  toys 
have  been  made,  that  the  sawdust  is  used  very  extensively 
for  this  purpose  also.  It  is  a  fact  that  there  are  five  hun- 
dred sawdust  merchants  in  the  city  of  New  York  alone,  and 
that  they  sell  what  is  generally  called  waste  to  the  value  of 
400,000  pounds  in  a  single  year. 

Since  the  slaughter  of  cattle,  sheep,  and  other  animals  on 
a  large  scale  was  begun  at  the  abattoirs  in  America,  France, 
and  other  countries,  the  valuable  articles  and  compounds 
which  have  been  made  from  dead  animals  is  really  amazing. 
In  some  of  the  American  abattoirs  the  carcass  of  a  single 
beef  may  enter  into  no  less  than  four  hundred  different 
articles,  ranging  from  the  beefsteak  for  the  family  table 
to  the  buttons  sewed  on  the  family  clothing.  Parts  of  the 
animals  formerly  discarded  go  into  medicines,  oils,  soaps, 


MAKING  MONEY  OUT  OP  WASTE  15 

brushes  and  combs,  mirrors,  household  necessaries  such  as 
handles  for  tools,  leather  for  harness  and  luggage  covers. 
Even  the  teeth  are  fashioned  into  studs  and  buttons.  A  list 
of  the  slaughter-house  by-products  which  are  now  utilized 
for  commercial  purposes  includes  hair,  bristles,  blood, 
bones,  horns,  hoofs,  glands,  and  membranes — from  which 
are  obtained  pepsin,  thymus,  thyroids,  pancreatin,  parotid 
substances,  and  suprarenal  capsules— gelatin,  glue,  fertili- 
zers, hides,  skins,  wool,  intestines,  neat's  foot  oil,  soap  stock, 
glycerin  from  tallow,  brewer's  isinglass,  and  albumen. 
Albumen  is  obtained  from  the  blood  of  the  slaughtered 
animals,  and  is  used  by  calico  printers,  tanners,  sugar  re- 
finers, and  others.  The  bones  coming  from  cooked  meat  are 
boiled,  and  the  fat  and  gelatin  which  result  are  used,  the 
former  to  make  soap,  the  latter  for  transparent  coverings 
for  chemical  preparations,  and  for  other  purposes.  The 
uncooked  bones  are  used  in  a  variety  of  ways.  From  the 
bones  of  the  feet  of  cattle  are  made  the  handles  of  tooth- 
brushes and  knives,  chessmen,  and  nearly  every  article  for 
which  ivory  is  suitable.  Combs,  the  backs  of  brushes,  and 
large  buttons  are  made  from  horns,  which  are  split  and 
rolled  flat  by  heat  and  pressure. 

Hoofs  are  utilized  according  to  their  color.  White  hoofs 
are  exported  largely  to  Japan,  to  be  made  into  various 
ornaments  and  imported  back  as  " Japanese  art  objects." 
From  striped  hoofs  buttons  and  horn  ornaments  are  made ; 
while  black  hoofs  find  service  in  the  manufacture  of  cyanide 
of  potassium  for  the  extraction  of  gold,  and  are  also  ground 
up  as  fertilizer.  From  the  feet  neat's  foot  oil  is  extracted, 
and  from  various  other  portions  of  the  body  various  other 
oils,  all  of  which  are  highly  valuable.  Substitutes  for 
butter,  such  as  butterin  and  oleomargarin,  are  made  by 
utilizing  the  fat  of  beef  and  hogs. 

In  the  textile  industry  the  making  of  value  out  of  waste 
has  been  truly  remarkable.  In  the  modern  woolen  factory 
no  fewer  than  five  products  are  obtained  by  methods  now 
in  vogue,  from  the  greasy  excretions  which,  after  circu- 


16  MODERN  SCIENCE  READER 

lating  through  the  animal's  system,  attach  to  the  wool  of  a 
sheep.  These  products  are  used  as  a  base  for  ointments 
and  toilet  preparations,  for  dressings  for  leather,  as  a  lubri- 
cant for  wool  and  other  animal  fibers,  and  in  conjunction 
with  certain  lubricating  oils.  At  one  large  plant  in  Amer- 
ica more  than  200,000  pounds  of  wool  are  " decreased" 
every  ten  hours.  From  two  million  to  three  million  dollars' 
worth  a  year  of  wool  fat  and  potash  are  estimated  to  have 
been  wasted  in  the  United  States  before  the  solvent  process 
of  extraction  came  into  general  use. 

In  the  industries  of  cotton  manufacturing  and  cottonseed 
oil  making,  scarcely  anything  is  allowed  to  go  to  waste. 
For  many  years  the  seed  of  the  cotton  plant  was  regarded 
as  without  value;  now  the  cottonseed  crop  of  the  United 
States  is  worth  about  one  fifth  of  the  total  cotton  crop  of 
the  country.  Among  the  principal  uses  of  cottonseed  oil 
are  its  part  in  making  lard  compound  and  white  cottolene, 
both  valuable  food  products.  Cottonseed  oil  is  also  used 
as  a  substitute  for  olive  oil,  by  soapmakers  in  the  making 
of  soap,  by  bakers,  and  also  in  the  manufacture  of  washing 
powders. 

The  leather  industry  is  equally  saving  in  the  matter  of 
wastes.  In  the  tanning  of  leather,  there  are  developed  as 
side  products,  scrap  and  skin,  from  which  glue  is  made; 
hair,  from  which  cheap  blankets  and  cloths  are  manufac- 
tured, and  waste  liquors  containing  lime  salts.  By  means 
of  a  special  apparatus  scraps  of  leather  are  converted  into 
boot  and  shoe  heels,  inner  soles,  etc.  What  is  called 
"shoddy"  leather  is  made  by  grinding  the  bits  of  leather 
to  a  pulp,  and  then  by  maceration  and  pressure  forming 
them  into  solid  strips. 


MODERN  EXPLOSIVES1 

BY  J.  S.  S.  BBAME 
Of  the  Royal  Naval  College,  Greenwich 

THE  subject  of  explosives  is  one  which  never  fails  to 
excite  interest  even  under  the  most  ordinary  conditions, 
doubtless  owing  to  the  enormous  potentiality  of  these  sub- 
stances, while  at  the  present  time  more  than  usual  attention 
is  directed  to  them,  it  being  scarcely  possible  to  read  a  daily 
paper  without  finding  some  reference  to  the  behavior  of 
various  modern  explosives  in  the  theater  of  war. 

Explosion  may  be  defined  as  chemical  action  causing 
extremely  rapid  formation  of  a  very  great  volume  of 
highly  expanded  gas,  this  large  volume  of  gas  being  gen- 
erally due  to  the  direct  liberation  by  chemical  action,  and 
the  further  enormous  expansion  by  the  heat  generated. 
Explosion  itself  may,  therefore,  be  regarded  as  extremely 
rapid  combustion,  while  the  effect  is  obtained  by  the  enor- 
mous pressure  produced,  owing  to  the  products  of  combus- 
tion occupying  probably  many  thousand  times  the  volume 
of  the  original  body.  The  effect  of  high  temperature  is 
seen  in  the  well-known  case  of  explosion  of  a  mixture  of 
hydrogen  and  oxygen,  where  if  the  original  mixture  and 
the  products  of  explosion  are  each  measured  at  the  same 
temperature  above  the  boiling  point  of  water,  a  less  volume 
of  gas  (water  vapor)  is  actually  found.  The  explosion  can 
only  have  been  produced  by  the  enormous  expansion  of 
this  vapor  in  the  first  place  by  the  heat  of  the  reaction. 
Such  an  explosion  when  carried  out  in  a  closed  bomb  with 
the  mixed  gases  under  ordinary  conditions  of  measure- 
ment produces  a  pressure  of  about  240  pounds  to  the  square 

*A  lecture   delivered   at   the  London  Institution  on   February   12, 
1900.     Published  in  Scientific  American  Supplement  for  May  12,  1900. 
2  17 


18  MODERN  SCIENCE  READER 

inch.  A  more  practical  illustration  is  seen  with  nitro- 
glycerin,  which  Nobel  found  yielded  about  1,200  times  its 
own  volume  of  gas  calculated  at  ordinary  temperatures  and 
pressures,  while  the  heat  liberated  expands  the  gas  to  nearly 
eight  times  its  normal  volume. 

Clearly,  tfyen,  a  substance  for  use  as  an  explosive  must 
be  capable  of  undergoing  rapid  decomposition  or  combina- 
tion with  the  production  of  large  volumes  of  gas,  and 
further  produce  sufficient  heat  to  greatly  expand  these 
gases,  the  ratio  of  the  volume  of  gases  at  the  moment  of 
explosion  to  the  volume  of  the  original  body  largely 
determining  the  efficiency  of  the  explosive. 

Explosives  may  be  divided  into  two  great  classes— me- 
chanical mixtures  and  chemical  compounds.  In  the  former 
the  combustible  substances  are  intimately  mixed  with  some 
oxygen-supplying  material,  as  in  the  case  of  gunpowder, 
where  carbon  and  sulphur  are  intimately  mixed  with 
potassium  nitrate;  while  guncotton  and  nitroglycerin  are 
examples  of  the  latter  class,  where  each  molecule  of  the  sub- 
stance contains  the  necessary  oxygen  for  the  oxidation  of 
the  carbon  and  hydrogen  present,  the  oxygen  being  in 
feeble  combination  with  nitrogen.  Many  explosives  are, 
however,  mechanical  mixtures  of  compounds  which  are 
themselves  explosive,  e.  g.,  cordite,  which  is  mainly  com- 
posed of  guncotton  and  nitroglycerin. 

Two  methods  are  in  common  use  for  bringing  about 
explosions— ignition  by  heat,  thus  bringing  about  ordinary 
but  rapid  combustion,  molecule  after  molecule  undergoing 
decomposition ;  and  detonation,  where  the  effect  is  infinitely 
more  rapid  than  in  the  first  case ;  in  fact,  it  may  be  regarded 
as  practically  instantaneous.  The  result  may  be  looked 
upon  as  brought  about  by  an  initial  shock  imparted  to  the 
explosive  by  a  substance— the  detonating  material— which 
is  capable  of  starting  decomposition  in  the  adjacent  layers 
of  the  explosive,  thus  causing  a  shock  to  the  next  layer,  and 
so  on  with  infinite  rapidity.  That  the  results  are  not  en- 
tirely due  to  the  mechanical  energy  of  the  liberated  gas 


MODERN  EXPLOSIVES  19 

particles  is  shown  by  the  fact  that  the  most  powerful  explo- 
sive is  not  the  most  powerful  detonator ;  neither  is  it  entirely 
due  to  heat,  since  wet  substances  undergo  detonation.  The 
probability  is  that  the  result  is  brought  about  by  vibrations 
of  particular  velocity  which  vary  for  different  substances, 
the  decomposition  being  caused  by  the  conversion  of  the 
mechanical  force  into  heat  in  the  explosive,  thus  bringing 
about  a  change  in  the  atomic  arrangement  of  the  molecule. 
According  to  Sir  Frederick  Abel's  theory  of  detonation, 
the  vibrations  caused  by  the  firing  of  the  detonator  are 
capable  of  setting  up  similar  vibrations  in  the  explosive, 
thus  determining  its  almost  instantaneous  decomposition. 

The  most  common  and  familiar  of  explosives  is  undoubt- 
edly gunpowder,  and  although  for  military  purposes  it  has 
been  largely  superseded  by  smokeless  powders,  yet  it  has 
played  such  an  important  part  in  the  history  of  the  world 
during  the  last  few  centuries  that  apart  from  military  uses 
it  is  even  now  of  sufficient  importance  to  demand  more  than 
a  passing  notice. 

Its  origin,  although  somewhat  obscure,  was  in  all  prob- 
ability with  the  Chinese.  Roger  Bacon  and  Berthold 
Schwartz  appear  to  have  rediscovered  it  in  the  latter 
years  of  the  thirteenth  and  earlier  part  of  the  fourteenth 
centuries.  It  was,  undoubtedly,  used  at  the  battle  of  Crecy 
(1346) .  The  mixture  then  adopted  appears  to  have  consisted 
of  equal  parts  of  the  three  ingredients— sulphur,  char- 
coal, and  nitre;  but  some  time  later  the  proportions,  even 
now  taken  for  all  ordinary  purposes,  were  introduced, 
namely : 

Potassium  nitrate 75  parts 

Charcoal   15  " 

Sulphur 10  " 

100  parts 

Since  gunpowder  is  a  mechanical  mixture,  it  is  clear  that 
the  first  aim  of  the  maker  must  be  to  obtain  perfect  incor- 
poration, and,  necessarily,  in  order  to  obtain  this,  the 


20  MODERN  SCIENCE  READER 

materials  must  be  in  a  very  finely  divided  state.  Moreover, 
in  order  that  uniformity  of  effect  may  be  obtained,  purity 
of  the  original  substances,  the  percentage  of  moisture 
present,  and  the  density  of  the  finished  powder  are  of 
importance. 

The  weighed  quantities  of  the  ingredients  are  first  mixed 
in  gun-metal  or  copper  drums,  having  blades  in  the  interior 
capable  of  working  in  the  opposite  direction  to  that  in  which 
the  drum  itself  is  traveling.  After  passing  through  a 
sieve,  the  mixture  (green  charge)  is  passed  on  to  the  in- 
corporating mills,  where  it  is  thoroughly  ground  under 
heavy  metal  rollers,  a  small  quantity  of  water  being  added 
to  prevent  dust  and  facilitating  incorporation,  and  during 
this  process  the  risk  of  explosion  is  greater  possibly  than  at 
any  other  stage  in  the  manufacture.  There  are  usually  six 
mills  working  in  the  same  building,  with  partitions  between. 
Over  the  bed  of  each  mill  is  a  horizontal  board,  the  "flash 
board,"  which  is  connected  with  a  tank  of  water  overhead, 
the  arrangement  being  such  that  the  upsetting  of  one  tank 
discharges  the  contents  of  the  other  tanks  onto  the  corres- 
ponding mill  beds  below,  so  that  in  the  event  of  an  accident 
the  charge  is  drowned  in  each  case.  The  "mill  cake"  is 
now  broken  down  between  rollers,  the  "meal"  produced 
being  placed  in  strong  oak  boxes  and  subjected  to  hydraulic 
pressure,  thus  increasing  its  density  and  hardness,  at  the 
same  time  bringing  the  ingredients  into  more  intimate  con- 
tact. After  once  more  breaking  down  the  material  (press 
cake)  the  powder  only  requires  special  treatment  to  adapt 
it  for  the  various  purposes  for  which  it  is  intended. 

Within  the  last  half-century  an  enormous  alteration  has 
taken  place  in  artillery,  the  old  smooth  bore  cannon,  firing 
a  round  shot,  having  gradually  given  place  to  heavy  rifled 
cannon,  firing  cylindrical  projectiles  and  requiring  very 
large  powder  charges.  This  has  naturally  had  its  influence 
on  the  powder  used,  and  modifications  have  been  introduced 
in  two  directions — first,  alteration  in  the  form  of  powder, 
and  second,  in  the  proportions  of  the  ingredients.  As  the 


MODERN  EXPLOSIVES  21 

heavier  guns  were  introduced,  a  large  grain  powder  which 
burned  more  slowly  was  adopted,  but  further  increase  in 
the  size  of  the  guns  led  to  the  introduction  of  pebble 
powders,  which  in  some  cases  consisted  of  cubes  of  over  an 
inch '  side.  Such  cubes  having  large  available  surface 
evolved  the  usual  gases  in  greater  quantity  at  the  start  of 
the  combustion  than  toward  the  finish,  since  the  surface 
became  gradually  smaller,  thus  causing  extra  strain  on  the 
gun  as  the  projectile  was  only  just  beginning  to  move. 
General  Rodman,  an  American  officer,  introduced  prism 
powder  to  overcome  this  difficulty,  the  charges  being  built 
up  of  perforated  hexagonal  prisms  in  which  combustion 
started  in  the  perforations  and  proceeding,  exposed  more 
surface,  the  prisms  finally  breaking  down  into  what  was 
virtually  a  pebble  powder. 

In  order  to  secure  still  further  control  over  the  pressure, 
modifications  in  the  proportions  of  the  ingredients  became 
necessary;  the  diminution  of  the  sulphur  and  increase  of 
the  charcoal  causing  slower  combustion,  and  moreover  the 
use  of  charcoal  prepared  at  a  low  temperature  giving  the 
so-called  "cocoa  powders." 

The  products  of  the  combustion  of  powder  and  its  manner 
of  burning  are  largely  influenced  by  the  pressure,  a  property 
well  illustrated  by  the  failure  of  a  red-hot  platinum  wire  to 
ignite  a  mass  of  powder  in  a  vacuum,  only  a  few  grains 
actually  in  contact  with  the  platinum  undergoing  combus- 
tion. The  gaseous  products  obtained  are  carbon  dioxide, 
carbon  monoxide,  and  nitrogen,  other  products  being  potas- 
sium carbonate,  sulphate,  and  sulphide.  The  calculated 
gas  yield  per  gram  at  0°  C.  and  760  mm.  pressure  is  264-6 
c.c.,  while  Nobel  and  Abel  actually  obtained  by  experiment 
263-74  c.c.,  numbers  agreeing  very  closely.  At  the  tem- 
perature of  explosion  this  volume  is  enormously  increased. 

In  18'32,  Braconnot  found  that  starch,  ligneous  fiber,  and 
similar  substances,  when  treated  with  strong  nitric  acid 
yielded  exceedingly  combustible  substances,  and  Pelouze,  in 
1838,  extended  the  investigation  to  cotton  and  paper. 


22  MODERN  SCIENCE  READER 

Schonbein  announced  in  1845  his  ability  to  make  an  explo- 
sive which  he  termed  guncotton,  and  a  year  later  Bottger 
made  a  similar  announcement,  and  on  a  conference  being 
held  between  these  chemists  their  methods  were  found  to 
be  identical.  The  method  was  not  disclosed  at  the  time, 
since  it  was  hoped  that  the  German  government  would 
purchase  the  secret,  but  in  a  very  short  time  several  investi- 
gators solved  the  problem,  and  attempts  to  make  the  new 
explosive  commercially  were  common.  Unfortunately  the 
earlier  product  was  unstable,  and  several  disastrous  acci- 
dents occurred  which  led  to  the  abandonment  of  the  experi- 
ments, except  in  Austria.  General  von  Lenk,  who  continued 
experimenting  in  that  country,  showed  that  if  sufficient 
care  was  taken  to  ensure  complete  nitration  and  to  remove 
all  traces  of  free  acid  from  the  finished  material,  the  sub- 
stance was  stable.  He  introduced  a  method  of  manufacture 
which  was  improved  by  Sir  Frederick  Abel  in  1865.  The 
physical  character  of  the  cotton  fiber  is  such  that  it  presents 
every  obstacle  to  the  removal  of  free  acid,  since  it  is  built 
up  of  capillaries,  but  by  reducing  these  tubes  to  the  short- 
est possible  length,  as  in  Abel's  process,  the  removal  of  acid 
is  facilitated. 

Since  water  is  a  product  of  the  reaction  of  nitric  acid  on 
cellulose,  the  nitric  acid  would  become  diluted,  forming 
"collodion  cotton "  instead  of  the  more  highly  nitrated 
guncotton,  and,  therefore,  sulphuric  acid  is  used  with  the 
nitric  acid  to  absorb  this  water,  the  usual  proportions  being 
3  parts  by  weight  of  sulphuric  acid  (1-84)  to  1  part  by 
weight  of  nitric  acid  (1-52).  Cotton  waste,  which  has  been 
picked,  cleaned,  cut  into  short  lengths,  and  dried,  is  dipped 
in  114-pound  charges  in  the  acid,  removed  after  five  or  six 
minutes,  the  excess  of  acid  squeezed  out,  and  the  cotton 
placed  in  cooled  earthenware  pots  for  some  twenty-four 
hours  for  nitration  to  be  completed.  The  guncotton  now 
goes  through  the  lengthy  process  for  removal  of  all  traces 
of  acid,  starting  with  the  removal  of  the  greater  portion  of 
the  acid  by  a  centrifugal  extractor,  washing  in  water  till 


MODERN  EXPLOSIVES  23 

no  acid  taste  can  be  detected,  boiling  in  water  till  free  from 
action  on  litmus,  reducing  to  pulp  in  a  hollander,  and 
finally,  the  thorough  washing  of  the  pulp  by  more  water. 
If  the  product  now  satisfies  the  tests  of  purity,  sufficient 
alkali— limewater,  whiting,  and  caustic  soda— is  added  to 
leave  from  one  to  two  per  cent,  in  the  finished  guncotton. 
The  pulp  is  drawn  up  into  a  vessel  from  which  it  can  be 
run  off  in  measured  quantities  into  molds  fitted  with  per- 
forated bottoms,  the  water  being  drawn  off  by  suction  from 
below,  and  finally,  a  low  hydraulic  pressure  is  brought  to 
bear  on  the  semi-solid  mass.  The  blocks  are  taken  to  the 
press  house  and  submitted  to  a  pressure  of  some  five  tons 
per  square  inch,  after  which  the  finished  block  will  contain 
from  12  to  16  per  cent,  of  water. 

From  its  chemical  reactions  guncotton  must  be  regarded 
as  an  ether  of  nitric  acid,  a  view  first  suggested  by 
Beehamp.  The  point  of  ignition  of  the  substance  has  been 
found  to  vary  considerably,  ranging  from  136°  to  223°  C., 
this  difference  being  probably  due  to  variations  in  composi- 
tion. Good  guncotton  usually  ignites  between  180°  and 
184°  C.  The  combustion  is  extremely  rapid  when  fired  in 
loose  unconfined  masses,  so  rapid,  in  fact,  that  it  may  be 
ignited  on  a  heap  of  gunpowder  without  affecting  the  latter. 
When  struck  between  hard  surfaces  guncotton  detonates, 
but  usually  only  in  that  portion  which  is  subjected  to  the 
blow.  The  volume  of  permanent  gases  evolved  by  the 
explosion  of  guncotton,  as  stated  by  different  observers,  has 
varied  greatly.  Macnab  and  Ristori  give  for  nitrocellulose 
(13-30  per  cent,  nitrogen)  673  c.c.  per  gram,  calculated 
at  0°  c.  and  760  mm.  Berthelot  estimates  the  pressure 
developed  by  the  detonation  of  guncotton  (sp.  gr.  1-1)  under 
constant  volume  as  24,000  atmospheres,  or  160  tons  per 
square  inch. 

Various  attempts  have  been  made  to  adapt  guncotton  for 
use  in  guns,  but  the  tendency  to  create  undue  pressure  led 
to  its  abandonment.  In  1868,  Mr.  E.  0.  Brown,  of  Wool- 
wich, showed  that  wet  guncotton  could  be  detonated  by  the 


24  MODERN  SCIENCE  READER 

use  of  a  small  charge  of  dry  guncotton  with  a  fulminate 
detonator,  and  since  it  can  be  stored  and  used  in  the  moist 
state,  it  becomes  one  of  the  safest  explosives  for  use  in 
submarine  mines,  torpedoes,  etc. 

Nitroglycerin  is  a  substance  of  a  similar  chemical  nature 
to  nitrocellulose,  the  principles  of  its  formation  and  puri- 
fication being  very  similar,  only  in  this  case  the  materials 
and  product  are  liquids,  this  rendering  the  operations  of 
manufacture  and  washing  much  less  difficult.  The  glycerin 
is  sprayed  into  the  acid  mixture  by  compressed  air  in- 
jectors, care  being  taken  that  the  temperature  during* 
nitration  does  not  rise  above  30°  C.  The  nitroglycerin 
formed  readily  separates  from  the  mixed  acids,  and  being 
insoluble  in  cold  water,  the  washing  is  comparatively  simple. 

This  explosive  was  discovered  by  Sobrero  in  1847. 
Nitroglycerin  is  an  oily  liquid  readily  soluble  in  most 
organic  solvents,  but  becomes  solid  at  three  or  four  degrees 
above  the  freezing  point  of  water,  and  in  this  condition  is 
less  sensitive.  It  detonates  when  heated  to  257°  C.,  or  by 
a  sudden  blow,  yielding  carbon  dioxide,  oxygen,  nitrogen, 
and  water.  Being  a  fluid  under  ordinary  conditions,  its 
uses  as  an  explosive  were  limited,  and  Nobel  conceived  the 
idea  of  mixing  it  with  other  substances  which  would  act 
as  absorbents,  first  using  charcoal  and  afterward  an  in- 
fusorial earth,  ' '  kieselguhr, "  and  obtaining  what  he  termed 
' '  dynamite. ' ' 

In  1875,  Mr.  Alfred  Nobel  found  that  "collodion  cotton" 
—soluble  guncotton— could  be  converted  by  treatment  with 
nitroglycerin  into  a  jelly-like  mass  which  was  more  trust- 
worthy in  action  than  the  components  alone,  and  from  its 
nature  the  substance  was  christened  "blasting  gelatin." 
The  discovery  is  of  importance,  for  it  was  undoubtedly  the 
stepping-stone  from  which  the  well-known  explosives  bal- 
listite,  filite,  and  cordite  were  reached.  In  1888,  Nobel 
took  out  a  patent  for  a  smokeless  powder  for  use  in  guns, 
in  which  these  ingredients  were  adopted  with  or  without 
the  use  of  retarding  agents.  The  powders  of  this  class 


MODERN  EXPLOSIVES  25 

are  ballistite  and  filite,  the  former  being  in  sheets,  the  latter 
in  threads.  Originally  camphor  was  introduced,  but  its 
use  has  been  abandoned,  a  small  quantity  of  aniline  taking 
its  place. 

Sir  Frederick  Abel  and  Professor  Dewar  patented  in 
1889  the  use  of  trinitrocellulose  and  nitroglycerin,  for  al- 
though, as  is  well  known,  this  form  of  nitrocellulose  is  not 
soluble  in  nitroglycerin,  yet  by  dissolving  the  bodies  in  a 
mutual  solvent,  perfect  incorporation  can  be  attained. 
Acetone  Is  the  solvent  used  in  the  preparation  of  " cordite," 
and  for  all  ammunition  except  blank  charges  a  certain  pro- 
portion of  vaseline  is  also  added.  The  combustion  of  the 
powder  without  vaseline  gives  products  so  free  from  solid 
or  liquid  substances  that  excessive  friction  of  the  projectile 
in  the  gun  causes  rapid  wearing  of  the  rifling,  and  it  is 
chiefly  to  overcome  this  that  the  vaseline  is  introduced, 
for  on  explosion  a  thin  film  of  solid  matter  is  deposited  in 
the  gun,  and  acts  as  a  lubricant. 

The  proportion  of  the  ingredients  are: 

Nitroglycerin    58  parts 

Guncotton  37     " 

Vaseline 5     " 

Guncotton  to  be  used  for  cordite  is  prepared  as  pre- 
viously described,  but  the  alkali  is  omitted,  and  the  mass 
is  not  submitted  to  great  pressure,  to  avoid  making  it  so 
dense  that  ready  absorption  of  nitroglycerin  would  not 
take  place.  The  nitroglycerin  is  poured  over  the  dried 
guncotton  and  first  well  mixed  by  hand,  afterward  in  a 
kneading  machine  with  the  requisite  quantity  of  acetone 
for  three  and  a  half  hours.  A  water  jacket  is  provided, 
since  on  mixing  the  temperature  rises.  The  vaseline  is 
now  added,  and  the  kneading  continued  for  a  similar 
period.  The  cordite  paste  is  first  subjected  to  a  prelimin- 
ary pressing,  and  is  finally  forced  through  a  hole  of  the 
proper  size  in  a  plate  either  by  hand  or  by  hydraulic  pres- 
sure. The  smaller  sizes  are  wound  on  drums,  while  the 


26  MODERN  SCIENCE  READER 

larger  cordite  is  cut  off  in  suitable  lengths,  the  drums  and 
cut  material  being  dried  at  100°  F.,  thus  driving  off  the 
remainder  of  the  acetone. 

Cordite  varies  from  yellow  to  dark  brown  in  color  ac- 
cording to  its  thickness.  When  ignited  it  burns  with  a 
strong  flame,  which  may  be  extinguished  by  a  vigorous 
puff  of  air.  Macnab  and  Ristori  give  the  yield  of  per- 
manent gases  from  English  cordite  as  647  c.c.,  containing 
a  much  higher  per  cent,  of  carbon  monoxide  than  the  gases 
evolved  from  the  old  form  of  powder.  Sir  Andrew  Noble 
failed  in  attempts  to  detonate  the  substance,  and  a  rifle 
bullet  fired  into  the  mass  only  caused  it  to  burn  quietly. 

Lyddite  is  probably  the  explosive  which  has  received 
most  notice  during  the  past  few  months.  In  1873,  Spren- 
gel,  in  a  paper  read  before  the  Chemical  Society,  stated 
that  "picric  acid  alone  contains  a  sufficient  amount  of 
oxygen  to  render  it,  without  the  help  of  foreign  oxidizers, 
a  powerful  explosive  when  fired  with  a  detonator.  Its 
explosion  is  almost  unaccompanied  by  smoke." 

Picric  acid  was  first  prepared  by  Woulfe  in  1771,  by 
treating  indigo  with  nitric  acid.  It  may  be  made  by  the 
direct  nitration  of  phenol  (carbolic  acid),  but  a  better 
result  is  obtained  by  first  dissolving  the  phenol  in  sulphuric 
acid,  forming  phenol  sulphonic  acid,  which  is  dissolved  in 
water,  and  nitrating  this  compound  with  nitric  acid  (14). 
On  cooling,  the  picric  acid  separates  out,  and  is  purified 
by  recrystallization  from  hot  water,  the  yellow  crystalline 
product  being  dried  at  a  temperature  not  exceeding 
100°  C. 

Picric  acid  containing  as  much  as  17  per  cent,  of  water 
can  be  detonated  by  a  charge  of  dry  picric  powder;  a  thin 
layer  may  also  be  exploded  by  a  blow  between  metal  sur- 
faces, its  sensitiveness  to  shock  being  greatly  increased  by 
warming,  for  at  a  temperature  just  below  its  melting  point 
a  pound  weight  falling  from  a  height  of  14  inches  will 
explode  it. 

The  sensitiveness  of  picric  acid  can  be  reduced  by  con- 


MODERN  EXPLOSIVES  27 

verting  the  powder  into  larger  masses,  this  being  accom- 
plished either  by  granulating  it  with  a  solution  of  collodion 
cotton  in  ether-alcohol,  as  in  the  earlier  forms  of  melinite, 
or  by  fusion,  which  takes  place  some  twenty  degrees  above 
the  boiling  point  of  water,  and  casting  directly  into  the 
shell,  as  in  lyddite  and  possibly  the  melinite  of  the  present 
day.  In  any  condition  perfect  detonation  would  yield 
only  colorless  gaseous  products  rich  in  carbon  monoxide, 
but  the  bursting  of  a  lyddite  shell  is  frequently  accom- 
panied by  a  yellow  smoke,  probably  formed  by  undecom- 
posed  acid  in  the  form  of  vapor.  The  shells  appear  to 
burst  in  two  distinct  ways,  in  one  case  giving  a  sharp, 
powerful  explosion  with  enormous  concussion  and  no  yel- 
low smoke,  and  the  other  a  heavy  report  with  the  yellow 
smoke,  the  two  results  appearing  to  be  due  to  perfect  de- 
composition in  the  first  instance,  while  in  the  second  partial 
decomposition  only  probably  occurs. 

Various  mixtures  of  picric  acid  or  its  salts,  together  with 
some  oxidizing  agent,  have  been  used  from  time  to  time, 
Abel's  powder  consisting  of  ammonium  picrate,  potassium 
nitrate,  and  a  small  quantity  of  charcoal. 

It  is  impossible  to  deal  with  the  numerous  other  explo- 
sives which  are  largely  in  use  in  such  a  survey  as  this,  and, 
therefore,  attention  has  been  confined  to  those  which  play 
the  most  active  part  in  modern  warfare. 


A  SKETCH  OF  THE  HISTORY  OF 
PROPELLANTS1 

BY  SIR  ANDREW  NOBLE,  D.  Sc.,  F.  R.  S. 

I  PURPOSE,  in  this  paper,  to  give  a  sketch  of  the  history 
of  propellants,  pointing  out  how  gunpowder  for  many 
centuries  was  the  sole  propellant  employed,  and  which 
remained  during  these  centuries  with  the  mode  of  manu- 
facture unimproved,  while,  even  by  very  great  men,  the 
wildest  and  most  divergent  ideas  were  entertained  as  to  the 
pressures  developed  by  its  explosion,  and  the  energy  which 
it  was  possible  to  realize. 

"The  origin  of  gunpowder  is,  I  am  afraid,  lost  in  remote 
antiquity.  It  was  supposed  to  have  been  known,  though 
not  as  a  propellant,  in  China  before  the  Christian  era,  but 
it  was  certainly  known  to  Roger  Bacon  about  12.G5,  who 
also  was  the  first  to  suggest  its  use  for  military  purposes. 
Its  first  employment  in  war  was  in  the  fourteenth  century, 
and  its  composition  and  mode  of  manufacture  during 
many  centuries  seem  to  have  undergone  but  little  change 
or  improvement. 

In  England  gunpowder  consisted  of  75  per  cent,  of 
saltpeter,  15  per  cent,  of  carbon,  and  10  per  cent,  of 
sulphur,  while  in  France  and  some  other  countries  the 
carbon  and  sulphur  were  in  equal  proportions,  viz.,  about 
12.5  per  cent. 

These  differences  in  proportions  affected  but  slightly  the 
energies  and  pressures  developed  by  fired  gunpowder,  but 
I  do  not  know  any  physical  fact  with  regard  to  which  such 

1  Abstract  of  a  paper  read  before  the  Institution  of  Engineers  and 
Shipbuilders  in  Scotland,  and  published  in  the  Scientific  American 
Supplement,  September  11,  1909. 

28 


HISTORY  OP  PROPELLANTS  29 

wide  differences  of  opinion  were  entertained  by  the  many 
eminent  men  who  iiave  written  upon  the  subject. 

De  la  Hire,  the  first  writer  on  gunpowder,  in  1702,  sup- 
posed that  the  propelling  force  of  gunpowder  was  due  to 
the  elasticity  of  the  air  between  the  grains,  and  that  the 
function  of  the  powder  was  merely  that  of  a  heating  agent. 

Robins,  however,  who  in  1743  read  before  the  Royal 
Society  of  London  a  paper  in  which  he  described  his  exper- 
iments, pointed  out  that  he  had  found  that  at  ordinary 
temperatures  and  atmospheric  pressure  the  generated  gas 
occupied  about  236  times  the  volume  of  the  gunpowder, 
and  that  at  the  temperature  of  explosion— which,  however, 
he  much  underestimated— the  maximum  pressure  would 
be  about  1,000  atmospheres  (6.6  tons  per  square  inch). 

He  considered,  and  cited  experiments  to  prove,  that  the 
whole  of  the  powder  he  employed  must  be  fired  before 
the  projectile  was  sensibly  moved  from  its  seat,  his  argu- 
ment being  that,  were  this  not  so,  a  much  greater  energy 
would  be  realized  when  the  weight  of  the  projectile  was 
materially  increased ;  but  this  experiment  showed  that  this 
was  not  so. 

Hutton,  in  1778,  read  before  the  Royal  Society  an  ac- 
count of  his  celebrated  researches  in  gunnery,  and  detailed 
the  experiments  from  which  he  deduced  the  maximum 
pressure  of  gunpowder  to  be  about  twice  that  given  by 
Robins,  or  about  2,000  atmospheres. 

Hutton,  like  Robins,  saw  that  the  energy  of  gunpowder 
was  due  to  the  elasticity  of  the  highly  heated  gases  gener- 
ated by  the  explosion  and,  assuming  that  the  powder  was 
instantaneously  ignited  and  that  the  pressure  was  as  he 
stated,  gave  formulae  for  deducing  the  pressure  of  the  gas 
and  the  velocity  of  the  projectile  at  any  point  of  the  bore. 

In  1797  Count  Rumford  communicated  to  the  Royal 
Society  his  celebrated  experiments  on  gunpowder,  and 
these  remained  for  many  years  the  only  experiments  from 
which  the  pressure  was  deduced  by  actual  measurement. 
In  Rumford 's  case  the  weight  lifted  by  the  pressure  of  the 


30  MODERN  SCIENCE  READER 

exploded  powder  was  assumed  to  be  the  correct  measure 
of  the  pressure. 

Rumford  made  two  series  of  experiments,  but  the  charges 
he  employed  were  very  small,  his  largest,  with  the  excep- 
tion of  one  by  which  his  vessel  was  destroyed,  being  18 
grains  or  about  l1^  grams. 

From  the  first  series  Rumford  deduced  that  with  a 
charge  at  a  density  of  unity  the  pressure  would  reach 
29,000  atmospheres.  But,  high  as  this  result  is,  Rumford 
considered  it  much  too  low,  and  from  a  second  series,  the 
results  of  which  were  very  discordant,  he  arrived  at  the 
conclusion  that  the  tension  of  exploded  gunpowder  such 
as  he  employed,  when  filling  completely  the  space  at  which 
it  was  inclosed,  wras  about  101,000  atmospheres. 

I  may  observe  that  the  mode  of  firing  the  powder  which 
Rumford  was  compelled  to  adopt,  viz.,  the  heating  of  the 
vessel  in  which  the  powder  was  confined  by  a  red-hot  ball, 
would  materially  increase  the  pressure,  and  he  further 
accounted  for  the  enormous  pressures  he  gave  not  being 
realized  in  guns,  by  assuming  that  the  combustion  of 
powder  in  artillery  and  small  arms  was  comparatively  slow 
and  approximated  to  the  rate  of  combustion  in  the  open 
air.  From  an  examination,  however,  of  Rumford 's  appa- 
ratus it  is  not  difficult  to  conjecture  both  how  he  supposed 
his  pressures  to  be  so  high,  and  also  how  some  of  his  results 
were  so  discordant. 

Passing  over  several  experimenters  or  writers  on  the 
subject,  I  must  refer  to  the  researches  of  Bunsen  and 
Shischkoff,  who  in  1857  published  the  results  of  their 
important  investigations.  The  powder  in  their  experi- 
ments was  not  exploded,  but  deflagrated  by  being  allowed 
to  fall  in  an  attenuated  stream  into  a  heated  bulb,  in 
which,  and  in  the  connected  tubes,  the  products  of  combus- 
tion were  collected. 

The  transformation  under  these  conditions  would  not  be 
quite  the  same  as  if  the  powder  had  been  exploded  under 
pressure,  but  a  careful  analysis  was  made  both  of  the  solid 


HISTORY  OF  PROPELLANTS  31 

products  and  of  the  gases.  The  weight  of  the  permanent 
gases  found  by  them  represented  only  31  per  cent,  of  the 
weight  of  the  powder,  and  occupied  at  0°  C.  at  atmospheric 
pressure  only  193  times  the  volume  of  the  unexploded 
powder.  They  fixed  the  temperature  of  explosion  at 
3,340°  C.  and  computed  that  the  maximum  pressure  which 
the  gas  can  attain,  which  it  may  approximate  to  but  can 
hardly  reach,  is  about  4,374  atmospheres,  or  29  tons  on  the 
square  inch. 

The  very  high  tension  of  101,000  atmospheres  suggested 
by  Count  Rumford  as  the  result  of  his  latest  experiments 
does  not  appear  ever  to  have  been  accepted,  but  within 
my  own  time  Piobert,  who  wrote  in  1864,  and  who  made 
a  number  of  important  experiments,  appears  to  have 
accepted  as  tolerably  correct  Rumford 's  first  series  of 
experiments,  and  fixed  the  tension  of  gunpowder  when 
fired  in  its  own  space  at  about  23,000  atmospheres,  while 
Cavalli  in  1867  arrived  at  nearly  the  same  conclusion, 
making  the  tension  about  24,000  atmospheres.  On  the 
other  hand,  I  find  that  text-books  in  use  at  the  Royal 
Military  Academy,  Woolwich,  so  late  as  1879  placed  the 
tension  of  fired  gunpowder  so  low  as  2,200  atmospheres, 
or,  say,  about  14  tons  per  square  inch. 

The  authors  who  ascribed  the  enormous  pressures  I  have 
named  much  underrated  the  rapidity  of  the  combustion  of 
gunpowder  under  pressure,  and  assumed  that  the  combus- 
tion was  comparatively  very  slow,  and  that  due  to  this 
slow  combustion  the  possible  maximum  pressure  was  never 
even  approximated  to  in  the  bores  of  guns;  but  it  has 
always  struck  me  as  remarkable  that  the  authorities  who 
accepted  these  high  tensions  did  not  test  the  accuracy  of 
their  assumptions  by  employing  the  simple  test  suggested 
by  Robins,  viz.,  to  find*  what  increase  of  energy  would 
be  realized  when  the  weight  of  the  shot  was  doubled, 
trebled,  etc. 

I  myself,  about  a  century  and  a  half  after  Robins, 
repeated  his  experiment  with  means  at  my  disposal  far 


32  MODERN  SCIENCE  READER 

greater  and  more  accurate  than  anything  he  could  have 
employed,  and  the  result  with  the  old  R.  L.  G.  powder  was 
as  follows: 

In  a  6-inch  gun  with  a  shot  weighing  30  pounds  the 
initial  velocity  was  2,126  foot-seconds,  and  the  energy 
realized  was  972  foot-tons.  With  the  weight  of  shot 
trebled— that  is,  increased  to  90  pounds,  the  total  velocity 
fell  to  1,370  foot-seconds  and  the  energy  increased  to  1,178 
foot-tons. 

Further  increases  in  the  weight  of  the  shot  to  120 
pounds,  150  pounds,  and  360  pounds  gave  energies  prac- 
tically identical,  viz.,  1,196,  1,192,  and  1,192  foot-tons, 
thus  entirely  confirming  Robins'  view. 

I  think  that  I  may  venture  to  say  that  the  question  of 
the  pressures  developed  by  fired  gunpowder  was  set  at  rest 
by  the  experiments  made  by  myself  and  described  in  a 
paper  by  Sir  F.  Abel  and  myself  in  the  transactions  of  the 
Royal  Society.  In  these  experiments  I  succeeded  in 
determining  for  the  three  powders  of  the  English  service, 
pebble,  rifle  large  grain,  and  fine  grain,  the  tension  of  the 
exploded  gas  at  all  densities  up  to  unity,  and  in  altogether 
retaining  the  whole  of  the  products  of  explosion,  even  of 
charges  of  several  pounds,  which  filled  entirely  or  nearly 
so  the  chambers  of  the  explosion  vessels.  The  results  of 
my  experiments  gave  for  a  density  of  unity  a  pressure  of 
about  6,500  atmospheres.  The  temperatures  of  explosion 
of  the  different  gunpowders  varied  considerably,  but  were 
generally  between  2,000°  C.  and  2,230°  C. 

I  have  never  been  able  to  understand  why  the  consider- 
able proportion  of  sulphur  was  so  long  retained  as  a  com- 
ponent of  gunpowder.  In  the  English  service,  shortly 
before  the  adoption  of  modern  propellants,  it  was  almost 
entirely  dispensed  with  in  cocoa  powder,  and  with  a  view 
of  studying  the  question  I  had  in  1883  four  experimental 
powders  made;  in  two  of  these  powders  sulphur  was  dis- 
pensed with,  or  nearly  so;  in  the  third,  the  amount  of 
sulphur  was  halved ;  and  in  the  fourth,  the  percentage  was 


HISTORY  OP  PROPELLANTS  33 

increased.  The  powder  without  sulphur  had  its  potential 
energy  increased  by  about  13  per  cent.,  while  that  with 
increased  sulphur  was  decreased  by  9  per  cent. 

The  early  methods  for  testing  the  potential  energy  and 
uniformity  of  gunpowder  were  very  rude,  and  permitted 
in  this  country  powders  to  be  passed  into  the  service  which 
showed  great  variations  in  potential  energy. 

My  attention  was  called  to  this  point  in  1860,  when, 
being  then  an  associate  member  of  the  Ordnance  Select 
Committee  and  carrying  out  experiments  for  that  body, 
I  found  that  the  variation  in  the  energy  developed  by  new 
powders  of  different  makes  occasionally  amounted  to  25 
per  cent. 

The  variation  admitted  at  the  present  day  in  passing 
propellants  is  about  2.8  per  cent. 

The  early  improvements  in  the  old  gunpowder  were  due 
to  the  labors  of  Major  Rodman,  U.  S.  A.,  who  seems  to 
have  been  the  first  to  appreciate  the  importance  of  a  suit- 
able and  uniform  density  of  the  powder,  but  also  by  the 
introduction  of  prismatic  powder  showed  that  it  was  pos- 
sible considerably  to  reduce  the  very  high  and  variable 
pressures  which  were  common  in  the  old  guns,  pressures 
which  would  not  be  permitted  in  the  much  stronger  guns 
of  the  present  day.  He  was  also  the  inventor  of  a  most 
ingenious  instrument  for  determining  the  pressure  devel- 
oped by  the  explosion  of  the  charge  in  the  chambers  or 
bores  of  guns,  and  Major  Rodman's  work  was  continued  in 
this  country  by  the  labors  of  the  first  explosive  committee, 
who  not  only  determined  with  great  accuracy  the  pressures 
of  the  propellants  and  the  velocity  of  the  projectiles  at  all 
points  of  the  bore,  but  also  increased  the  velocity  by  over 
220  foot-seconds,  thus  increasing  the  energy  developed  by 
about  33  per  cent.,  while  the  maximum  pressure  was  re- 
duced by  about  the  same  percentage— a  matter  of  very 
great  importance  in  the  case  of  all,  but  especially  of 
breech-loading  guns. 

But  I  fear  I  have  detained  you  too  long  with  the  old 
3 


34  MODERN  SCIENCE  READER 

gunpowders,  and  perhaps  the  easiest  way  of  showing  the 
striking  difference  between  the  old  gunpowders  and  some 
of  the  modern  propellants  is  to  give  you  two  tables1  exhibit- 
ing, first,  the  volume  of  gas  generated  by  the  explosion; 
second,  the  units  of  heat  generated ;  and  third,  the  product 
of  the  units  of  heat  and  volumes  of  gas,  which  represents 
approximately  the  comparative  potential  energy  of  the 
explosives. 

For  cordite,  the  first  modern  propellant  adopted  in  Eng- 
land, we  were  indebted  to  the  labors  of  the  late  Sir  F.  Abel 
and  Sir  James  Dewar,  and  the  value  of  the  propellant  is 
sufficiently  shown  by  the  fact  that  with  the  same  maxi- 
mum pressure  artillerists  have  been  able  to  more  than 
double  the  energy  of  the  projectile. 

It  will  be  observed  that  the  figures  I  give  as  representing 
the  comparative  energies  of  the  old  propellants  vary  from 
200,438  to  179,478,  while  the  similar  figures  for  the  modern 
explosives  vary  from  1,090,873  to  851,212,  or  more  than 
four  times  as  great,  and  the  diagram  I  also  show  exhibits 
the  comparative  pressures  developed  up  to  the  density  of 
5,  thus  at  the  density  of  5  the  pressure  of  gunpowder  is 
about  1,700  atmospheres— amide  powder  3,500  atmos- 
pheres—while the  modern  explosives  at  the  same  density 
lie  between  pressures  of  8,600  and  7,200  atmospheres. 

Turning  now  to  the  total  volumes  of  gas  generated  and 
the  units  of  heat  developed  by  the  explosion,  I  find  in  the 
various  explosions  I  have  examined  the  same  general  rules 
hold.  With  the  increase  of  density  the  volumes  of  gas 
decrease  and  the  units  of  heat  increase. 

Now,  I  have  pointed  out  that  with  the  increase  of  density 
there  is  in  all  cases  a  decrease,  in  most  cases  a  considerable 
decrease  in  the  volume  of  gas,  and  as  the  pressures  devel- 
oped increase  much  more  rapidly  than  the  density,  it  is 
obvious  that  with  increase  of  density  there  must  be  a  very 
considerable  increase  of  temperature. 

At  a  density  of  0.5  I  place  the  temperatures  of  the  high 
JSee  original  publication  if  detailed  information  is  desired. 


HISTORY  OF  PROPELLANTS  35 

explosives  I  have  examined  as  varying  between  4,000°  and 
5,000°  C.  I  need  not  say  that  at  less  densities  they  are 
very  much  lower. 

I  have  mentioned  that  the  percentages  of  the  several 
gases  generated  by  the  explosion  vary  greatly,  dependent 
upon  the  pressure  under  which  the  explosion  takes  place, 
and  I  shall  exhibit  to  you  three  diagrams,  in  two  of  which 
there  are,  with  increase  of  density,  large  increases  in 
volume,  and  in  the  third  a  considerable  decrease. 

All  of  the  new  propellants  develop  on  explosion  a  very 
much  higher  temperature  than  did  the  old  gunpowders, 
and  the  introduction  of  armored  vessels  has  necessitated 
the  employment  of  guns  fifteen  or  sixteen  times  heavier 
than  the  guns  in  use  fifty  years  ago,  and  capable  of  giving 
to  their  projectiles  energies  nearly  fifty  times  as  great. 

Now,  as  regards  the  serious  question  of  erosion,  in  the 
case  of  the  very  large  guns  it  is  important  to  remember 
that  while  the  surface  of  the  bore  subject  to  the  more 
violent  erosion  increases  approximately  as  the  caliber  or 
a  little  more,  the  charge  of  the  propellant  required  to  give 
to  similar  projectiles  the  same  maximum  velocity  increases 
as  the  cube  of  the  caliber ;  and,  consequently,  unless  special 
arrangements  as  to  the  projectile  are  made,  or  other  means 
adopted,  the  life  of  the  largest  guns  before  re-lining,  must 
be  short  when  compared  with  that  of  smaller  guns. 

It,  therefore,  becomes  a  matter  of  great  importance  that 
attention  should  be  given  to  the  best  method  of  reducing 
erosion  when  very  large  charges  are  used,  either  by  lower- 
ing the  temperature  of  explosion  of  the  propellant,  or 
possibly  by  introducing  with  the  charge  some  cooling 
agent. 

As  regards  the  first  of  these  points  some  very  consider- 
able advance  has  been  made,  but  I  venture  to  think  that  the 
question  of  erosion  has,  at  least  in  this  country,  hardly 
received  sufficient  attention,  and  that,  in  some  respects, 
mistaken  notions  as  to  the  amount  of  erosion  with  reduced 
charges  are  entertained. 


ARTIFICIAL  SILK1 

BY  JOSEPH  CASH 

IT  is  a  trite  saying  that  all  inventions  are  creatures  of 
evolution.  I  shall  give  a  short  description,  therefore,  of 
a  few  attempts  to  produce  the  appearance  of  silk  before 
the  perfected  artificial  article  of  to-day  became  an  estab- 
lished fact.  Some  were  partially  successful  in  effect  and 
others  have  been  a  pronounced  commercial  success,  adding 
greatly  to  the  variety  of  the  cheaper  textile  fabrics. 

SPUN  GLASS  is  probably  the  earliest  production  which 
resembles  natural  silk.  The  thread  is  perfectly  flexible, 
possessing  great  brilliancy,  and  is  produced  in  a  variety  of 
colors.  The  feel  to  the  touch  is  soft  and  smooth ;  it  can  be 
woven  into  many  textiles,  and  is  specially  useful  in  milli- 
nery articles  where  warmth  is  not  a  necessary  adjunct. 

POLISHED  OR  DIAMOND  COTTON  is  a  lustrous-looking  arti- 
cle, and  in  the  fine  sizes,  or  counts  as  it  is  called  in  the 
trade,  is  silky  in  appearance  and  soft  to  the  touch.  An 
enormous  trade  is  done  in  this  article  for  dress  goods,  as 
it  is  often  used  in  combination  with  silk.  The  process  of 
producing  it  is  very  simple,  waxy  and  starchy  substances 
being  put  on  the  thread  in  a  liquid  emulsion ;  the  yarn  is 
then  transferred  to  a  polishing  machine  with  rapid-revolv- 
ing brushes,  which  completes  the  process. 

MERCERIZED  COTTON.  A  process  for  giving  a  silky  ap- 
pearance to  cotton  has  lately  been  brought  to  the  notice  of 
manufacturers  with  very  satisfactory  results.  The  process 
is  practised  by  most  cotton  dyers,  there  being  no  valid 
patent.  The  name  is  derived  from  the  inventor,  John 
Mercer,2  who  discovered  the  process  in  1844.  The  cotton 

Abstract,  published  in  the  Journal  of  the  Society  of  Arts,  1899. 
2  Note  the  coincidence  that  a  silk  merchant  is  called  a  mercer  in 
England. — ED. 


ARTIFICIAL  SILK  37 

yarn  is  passed  through  strong  solutions  of  caustic  lye. 
The  yarn  must  be  at  full  tension  during  the  whole  opera- 
tion, even  until  it  is  quite  dry.  Mercer's  theory  of  the 
action  of  caustic  soda  is  that  received  to-day,  viz.,  that 
the  mercerized  yarn  is  a  hydrate  of  cellulose,  the  first 
action  being  the  formation  of  a  compound  of  sodium  oxide 
and  cellulose.  The  subsequent  washing  replaces  the 
sodium  oxide  by  water,  which  is  held  by  the  cellulose  like 
the  metallic  oxide.  Such  a  theory  as  this  gives  us  very 
little  light  on  the  matter,  and  does  not  explain  the  differ- 
ence between  the  hydrate  formed  and  the  original  cotton. 
It  can  be  dyed  any  color  without  materially  affecting  the 
brilliancy  which  has  been  imparted  to  it  by  the  mercerizing 
process. 

COLLODION  SILK.  Several  persons  have  given  their  atten- 
tion to  the  perfecting  of  the  manufacture  of  collodion  silk, 
among  whom  are  Count  Hilaire  de  Chardonnet,  Dr.  Leh- 
ner,  and  Nobel  of  cordite  fame.  The  different  systems 
vary  only  in  detail,  so  I  shall  describe  the  most  successful 
one,  known  as  the  Chardonnet  silk.  I  first  saw  this  arti- 
ficial silk  at  the  Paris  Exhibition  of  1889,  where  it  obtained 
a  "Grand  Prix."  Previous  exhibits  were  made  of  artificial 
silk  in  1878,  but  no  commercial  success  was  attained  for 
many  years. 

A  public  company  for  the  manufacture  of  artificial  silk 
by  the  Chardonnet  process  has  been  formed  in  England. 
The  factory,  extending  over  two  acres,  is  at  Wolston,  on 
the  river  Avon,  near  Coventry,  and  will  be  capable  when 
filled  with  machinery  of  producing  7,000  pounds  of  silk 
per  week. 

The  first  stage  of  manufacture  is  the  nitration  of  cotton 
or  wood  pulp,  producing  pyroxyline,  discovered  by  Pelouze 
in  1838.  The  greatest  care  must  be  employed  in  conduct- 
ing this  operation,  as  it  is  the  most  important  one  in  the 
whole  process;  mistakes  sometimes  occur  even  at  the  long 
established  factory  at  Besancon  in  France.  The  process 
oi  nitration  of  cellulose  is  the  displacement  of  a  few  mole- 


38  MODERN  SCIENCE  READER 

cules  of  hydrogen  by  nitric  peroxide.  There  are  several 
varieties  of  pyroxyline  which  are  obtained  by  using  differ- 
ent mixtures  of  acid.  The  highest  nitro-cotton  product, 
guneotton,  or  trinitrocellulose,  is  useless  for  the  manu- 
facture of  artificial  silk,  as  it  is  insoluble  in  a  mixture  of 
alcohol  and  ether.  To  obtain  the  pyroxyline  or  binitrocel- 
lulose  suitable  for  the  production  of  collodion  for  our  pur- 
pose, a  mixture  of  15  volumes  of  sulphuric  (H2  S04)  and 
12  volumes  of  nitric  acid  (HN03)  is  made;  two  pounds  of 
bleached  raw  cotton  is  then  taken  and  put  into  an  earthen- 
ware jar  with  about  three  gallons  of  mixed  acid;  this  is 
left  standing  for  four  to  five  hours,  when  the  nitration  is 
complete.  The  chemical  reaction  may  be  expressed  by  the 
following  formulae : 

C6  H10  05  +  2HN03  +  H2  S04  = 
C6  H8  (N03)2  03  +  (2H2  0  +  H2  SOJ 

The  object  of  the  sulphuric  acid  (H2  S04)  is  to  take  up 
hygroscopically  the  excess  of  water  produced,  leaving  the 
nitric  acid  (HN03),  of  which  there  is  always  an  excess. 
The  only  known  way  of  testing  the  quality  of  the  pyroxy- 
line is  the  use  of  the  microscope  in  conjunction  with  the 
polariscope.  A  small  piece  of  pyroxyline  is  taken  from 
one  of  the  jars,  thoroughly  washed  in  water  and  dried ;  it 
is  then  moistened  with  alcohol,  when  the  colors  exhibited 
should  be  in  exact  proportion  which  practice  has  proved  to 
give  the  best  results. 

The  pyroxyline  is  now  taken  out  of  the  pots  and  sub- 
jected to  pressure  to  extract  all  the  acid  possible.  This 
extracted  acid  is  not  wasted,  but  is  renovated  with  a  mix- 
ture of  new  acid  and  used  again  for  more  cotton.  From 
the  press  the  pyroxyline  is  taken  to  the  washing  room  and 
at  once  put  into  the  washing  machine,  called  a  hollander, 
and  similar  to  those  used  in  paper  making  for  washing 
pulp. 

This  washing  continues  for  from  12  to  15  hours  until 
the  acid  is  thoroughly  eliminated ;  from  thence  the  material 


ARTIFICIAL  SILK  39 

is  removed  to  a  centrifugal  machine  to  extract  the  moisture, 
which  must  not  exceed  28  per  cent.;  if  too  much  water  is 
present,  the  collodion  will  not  be  tenacious  and  therefore 
will  not  spin.  The  pyroxyline  is  now  ready  for  dissolving 
in  a  mixture  of  alcohol  and  ether.  The  pyroxyline  is 
placed  in  a  cylinder,  with  a  mixture  of  40  parts  alcohol 
and  60  parts  ether ;  the  cylinder  is  then  hermetically  sealed 
and  made  to  revolve  slowly  for  12  hours,  when,  if  the 
pyroxyline  is  good,  all  should  be  dissolved;  the  resulting 
mixture  is  collodion.  The  next  process  is  the  filtration. 
Upon  this  depends  the  amount  of  production  from  the 
spinning  machinery,  supposing  the  collodion  be  good.  The 
filtering  is  to  eliminate  every  particle  of  suspended  matter 
which  may  exist  in  the  collodion  before  it  arrives  at  the 
spinning  machines,  as  grit  and  seeds  from  the  cotton,  or 
suspended  matter  in  the  washing  water,  or  even  trinitro- 
cellulose,  which  is  insoluble  in  alcohol  and  ether,  but  this 
latter  should  never  occur  in  good  silk  collodion.  Each 
filter  contains  a  sheet  of  cotton  wool  between  calico.  A 
pressure  of  15  atmospheres  is  required  to  force  the  collodion 
through  the  filters;  it  is  therefore  first  passed  into  a 
hydraulic  press,  by  the  aid  of  which  it  is  forced  through 
the  filters  and  into  the  collodion  reservoir,  where  it  should 
remain  as  long  as  possible  to  allow  any  bubbles  to  rise  to 
the  top,  for  should  they  pass  into  the  glass  silkworms,  the 
continuity  of  the  thread  would  be  broken. 

A  pressure  of  40  to  45  atmospheres  is  required  to  force 
the  collodion  from  these  reservoirs  to  the  spinning  ma- 
chines, which  are  constructed  with  pipes  running  on  each 
side.  Into  these  pipes  are  screwed  a  number  of  taps  with 
a  glass  capillary  tube  fixed  on  the  end,  called  a  silkworm, 
through  which  the  collodion  is  forced  by  the  pressure  be- 
fore mentioned;  immediately  it  comes  into  contact  with 
the  air  it  solidifies,  enabling  the  operative  to  take  hold  of 
the  thread  or  silk,  as  it  can  now  be  called,  and  convey  it 
to  the  bobbin.  From  twelve  to  twenty-four  of  these 
threads  are  run  together  on  to  one  bobbin,  according  to  the 


40  MODERN  SCIENCE  READER 

size  of  silk  required,  as  is  the  case  with  natural  silk.  The 
silk  would  soon  dry  by  the  evaporation  of  the  alcohol  and 
ether  if  left  exposed  to  the  air;  it  is  therefore  kept  moist 
by  damp  cloths  to  facilitate  the  next  process  of  throwing 
and  twisting.  This  is  accompanied  by  putting  on  the  silk 
the  required  number  of  turns  or  twists  per  inch.  The 
reeling  or  skeining  of  the  silk  into  a  given  number  of  yards 
in  each  skein  is  the  next  operation.  One  thousand  or  two 
thousand  yards  is  the  usual  quantity,  and  according  to 
the  weight  of  skein  so  is  the  size  designated.  The  Char- 
donnet  silk  is  about  30  per  cent,  heavier  in  S.G.  than  na- 
tural silk,  so  the  comparison  of  sizes  is  easily  arrived  at. 
The  silk  is  still  damp,  and  should  now  have  the  remaining 
alcohol  and  ether  dried  out  of  it.  The  inventor  claims  this 
to  be  one  of  the  most  important  points  to  give  the  silk  good 
dyeing  properties. 

The  silk  at  this  point  of  manufacture  is  very  inflam- 
mable and  quite  unfit  for  use  in  textile  goods,  therefore 
a  process  called  denitration  is  next  carried  out  which  re- 
converts our  product  into  cellulose,  now  very  different  in 
appearance  from  the  raw  cotton  we  commenced  with,  but 
practically  the  same  in  chemical  composition. 

One  of  the  substances  used  for  this  purpose  is  sulphy- 
drate  of  calcium,  and  the  chemical  reaction  may  be  ex- 
pressed by  the  following  formulae: 

C,H8(N08)o  03  +  2  Ca  H2S2= 
C6H1005  +  2  Ca  N02  +  H2S  +  S2. 

The  silk,  now  it  is  finished,  requires  no  precautions  in 
manufacturing  more  than  cotton,  in  fact  less,  as  there 
should  be  no  loose  fiber  which  can  detach  itself  from  the 
thread. 

The  bleaching  is  carried  out  in  the  usual  way  for  vege- 
table fibers  with  chloride  of  lime  and  acid. 

Up  to  the  present  time  artificial  silk  has  always  been 
used  in  conjunction  with  other  fibers  in  textile  goods;  the 
friction  of  weaving  has  a  tendency  to  split  the  threads  if 


ARTIFICIAL  SILK  41 

used  in  warps,  but  this  objection  will  no  doubt  be  over- 
come. 

Mantles  for  the  incandescent  gas  light  are  manufactured 
of  artificial  silk,  it  being  found  that  the  salts  of  the  rare 
metals  can  be  mixed  with  the  collodion  with  greater 
economy  than  with  any  other  thread. 

For  braids  and  such  classes  of  trimmings  it  is  much  more 
brilliant;  for  covering  electric  wires  and  all  electric  work 
it  is  better.  Large  works  are  in  operation  at  Besangon, 
in  France,  producing  7,000  pounds  per  week;  but  the  de- 
mand is  so  great  that  they  are  making  extensions  to  their 
works  to  enable  them  next  January  to  produce  2,000 
pounds  per  day.  The  production  at  Sprietenbach  is  600 
pounds  daily.  Other  factories  are  about  to  be  established 
in  Belgium  and  Germany. 

Collodion  silk  can  never  replace  natural  silk  in  articles 
where  warmth  is  required,  its  composition  being  vegetable, 
and  that  of  silk  analogous  to  horn  and  hair^or  wool.  The 
artificial  product  is  to  be  preferred,  being  more  durable 
than  the  natural  when  the  latter  is  weighted  in  the  dyeing 
up  to  100  per  cent,  in  colors,  and  as  high  as  300  per  cent, 
in  black. 


THE  CREATORS  OF  THE  AGE  OF 
STEEL1 

BESSEMER,  SIEMENS,  WHITWOETH,  AND  THOMAS 

THERE  is  more  of  truth  than  poetry  in  giving  to  the  era 
beginning  with  the  year  1850  the  name  of  "The  Age  of 
Steel."  The  metallurgical  inventions  and  discoveries 
which  mark  abruptly  that  period  have  effected  a  revolution 
in  the  industry  of  the  world.  Steel  is  to  us  what  iron  was 
to  our  grandfathers;  what  bronze  was  to  the  armies  that 
sat  in  league  before  Troy;  what  stone  was  to  the  naked 
savages  that  dwelt  in  the  caves  of  Gaul  before  the  begin- 
ning of  history.  The  very  web  and  woof  of  modern  civil- 
ization is  woven  out  of  steel.  The  production  of  steel  in 
1882  was  as  great  as  the  crude  iron  product  of  1850.  The 
metal  is  omnipresent ;  it  has  replaced  iron,  wood,  brass,  and 
copper.  The  rails,  ships,  cannon,  and  machinery  of  the 
world  are  steel.  The  best  definition  yet  given  of  man  is 
that  he  is  a  tool-using  animal;  his  tools  are  steel,  and  the 
tools  wherewith  he  makes  his  tools  are  steel. 

As  Carlyle  says,  "We  are  to  bethink  us  that  the  epic 
verily  is  not  Arms  and  the  Man,  but  Tools  and  the  Man— an 
indefinitely  wider  kind  of  epic.  Man  is  a  tool-using  ani- 
mal. Weak  in  himself  and  of  small  stature,  he  stands  on  a 
basis,  at  most  for  the  flattest  solid,  of  some  half  square- 
foot,  insecurely  enough;  he  has  to  straddle  out  his  legs 
lest  the  very  wind  supplant  him.  Feeblest  of  bipeds! 
Three  quintals  are  a  crushing  load  for  him;  the  steer  of 
the  meadow  tosses  him  aloft  like  a  waste-rag.  Neverthe- 
less, he  can  use  tools;  can  devise  tools;  with  these  the 
granite  mountain  melts  into  light  dust  before  him;  he 

*A  review  published  in  the  St.  Louis  Globe-Democrat,  1884. 

4Q 


CREATORS  OF  THE  AGE  OF  STEEL     43 

kneads  glowing  iron  as  if  it  were  soft  paste;  seas  are  his 
smooth  highway ;  winds  and  fire  his  unwearying  steeds. ' ' 

The  conquest  of  the  world  man  is  achieving  with  steel, 
and  who  the  men  were  that  have  put  this  weapon  in  the 
hands  of  man,  Jeans  tells  us  in  the  book  whose  title  pre- 
cedes this  article. 

The  two  first  and  greatest  inventors  in  the  trade  reaped 
no  reward.  Dudley  in  1618  learned  a  way  to  smelt  iron 
with  coal,  and  died  in  obscurity.  Henry  Cort,  in  the  mid- 
dle of  the  eighteenth  century,  invented  the  puddling  proc- 
ess, and  would  have  starved  but  for  a  pension  of  £200 
given  him  by  Pitt.  Honors  and  wealth,  however,  were 
showered  lavishly  on  the  bright  galaxy  of  men  whose 
names  are  enrolled  in  the  list  of  the  creators  of  the  age  of 
steel.  The  story  of  their  triumphs  over  matter  and  circum- 
stance makes  one  of  the  most  interesting  chapters  in  the 
history  of  industry. 

SIR  HENRY  BESSEMER.— Among  the  French  refugees 
driven  to  England  by  the  Terror  was  Anthony  Bessemer. 
A  learned  and  little  man,  he  speedily  accumulated  a  hand- 
some property,  the  reward  of  an  inventive  ingenuity  in- 
herited and  developed  by  his  illustrious  son.  Among  many 
other  profitable  processes  the  elder  Bessemer  discovered 
that  an  alloy  of  copper,  tin,  and  bismuth  was  the  best  for 
type  metal.  His  process  he  kept  secret,  claiming  that  the 
superiority  of  his  type  came  from  the  angles  at  which  it 
was  cut.  It  lasted  twice  as  long  as  the  other  types,  and 
sold  all  over  England.  The  youngest  son  of  this  gentleman 
was  Henry  Bessemer,  born  at  Charlton  in  1813.  His  first 
attack  upon  destiny  was  made  in  improving  the  stamps 
upon  public  documents.  He  invented  a  stamp  which  could 
not  be  duplicated  or  detached,  which  was  adopted  by  the 
Government,  and  for  which  not  a  penny  was  ever  paid  to 
the  young  inventor.  His  next  work  was  a  machine  for 
making  patterns  of  figured  velvet,  a  type-casting  machine, 
and  a  type-composing  machine.  While  working  upon  this 
latter  machine  he  was  struck  by  the  fact  that  bronze 


44  MODERN  SCIENCE  READER 

powder  when  manufactured  sold  for  twelve  shillings  a 
pound,  while  the  raw  material  cost  but  eleven  pence.  The 
difference  he  knew  must  come  from  the  process  of  manu- 
facturing, a  process  which  he  at  once  began  to  study.  The 
article  came  altogether  from  Nuremberg  in  Germany,  and 
no  one  in  England  could  tell  him  how  it  was  made.  For 
nearly  two  years  he  studied  this  problem,  earning  success  in 
the  end  by  his  infinite  industry.  He  had  not  learned  to  have 
confidence  in  the  patent  laws,  and  he  determined  to  keep  his 
invention  a  secret.  A  friend  advanced  him  £10,000,  works 
were  erected,  the  machinery  being  made  in  different  parts 
of  England.  Five  operatives  were  employed,  at  large 
salaries,  under  pledge  of  secrecy,  and  the  bronze  was 
turned  out  at  a  cost  of  less  than  4  shillings  a  pound.  To 
this  day,  although  forty  years  have  elapsed,  no  one  has 
surprised  the  secret.  Sir  Henry  Bessemer  has  years  since 
rewarded  the  faithfulness  of  his  workingmen  by  giving 
them  the  factory  and  the  business,  and  they  too  have  made 
fortunes  out  of  the  trade. 

Between  1844  and  1850  Bessemer  patented  machines  for 
the  manufacture  of  paints,  oils,  and  varnishes ;  for  the  sepa- 
ration of  sugar  from  molasses;  for  a  drainage  pump  capa- 
ble of  discharging  twenty  tons  of  water  per  minute;  a 
machine  for  polishing  plate-glass,  substituting  a  vacuum 
for  the  plaster-bed.  Each  of  these  was  as  meritorious  as 
unique,  and  as  profitable  as  it  was  ingenious. 

This  much  will  show  the  surprising  versatility  of  the 
man,  and  enable  the  reader  to  grasp  the  character  that 
revolutionized  modern  industry. 

The  Crimean  war  turned  Bessemer 's  attention  to  ord- 
nance ;  he  produced  a  projectile  which  rotated  without  the 
aid  of  rifling  from  the  gun,  and  made  many  improvements 
in  the  guns  themselves.  The  English  authorities  ridiculed 
his  improvements;  the  Emperor  Napoleon  was  greatly 
struck  with  them,  and  requested  Bessemer  to  continue  his 
experiments  at  the  expense  of  France.  At  one  of  the 
subsequent  tests  Commander  Minie  said:  "The  shots  rotate 


CREATORS  OF  THE  AGE  OF  STEEL     45 

properly,  but  if  you  cannot  get  a  stronger  metal  for  your 
guns,  such  heavy  projectiles  will  be  of  little  use."  That 
remark  produced  the  Bessemer  process  for  making  steel. 
He  knew  nothing,  absolutely  nothing,  about  metallurgy; 
he  had  no  idea  how  any  improvement  was  to  be  made,  and 
yet  he  resolved  to  attack  this  problem  of  steel  making  and 
solve  it. 

Prior  to  1740  the  best  steel  was  made  in  Hindostan,  and 
cost  £10,000  a  ton.  A  watchmaker  named  Huntsman,  after 
a  long  course  of  experiments  in  that  year,  produced  equally 
good  steel,  which  could  be  made  at  £100  a  ton,  and  for  a 
century  Huntsman's  process  had  been  used  without  im- 
provement. In  the  English  process  before  1740  the  bars 
of  iron  were  heated  with  a  cement  of  hardwood  charcoal 
dust,  which  added  carbon  to  the  metal,  and  made  what  is 
called  "blistered  steel."  The  heating  had  to  be  continued 
several  days.  This  was  as  yet  unfit  for  forging,  and  the 
bars  had  to  be  broken  into  lengths  of  about  eighteen  inches, 
raised  to  a  welding  heat,  and  hammered  with  a  "tilting 
hammer,"  a  process  which  produced  good  steel.  Hunts- 
man took  the  blistered  steel,  broke  it  up  into  bits,  put  it 
into  crucibles  with  coke  dust,  fused  the  whole,  and  so  made 
cast  steel. 

When  Bessemer  began  his  work,  this  process  was  the 
only  one  in  use.  The  iron  had  first  to  be  melted  into  pigs, 
the  pigs  heated  with  carbon  into  blistered  steel,  the  blis- 
tered steel  broken  up  and  remelted  with  carbon  into  steel 
ingots  in  crucibles  which  could  not  hold  more  than  thirty 
pounds  each.  Bessemer 's  experiment  produced  first  a  cast 
iron  better  and  stronger  than  any  known  before. 

At  the  end  of  eighteen  months  the  idea  struck  him  of 
rendering  cast  iron  malleable  by  the  introduction  of  atmos- 
pheric air.  A  great  many  experiments  followed,  all  of 
them  moderately  successful.  Mechanical  difficulties  almost 
insuperable  stood  in  the  way.  At  last  he  constructed  a 
circular  vessel  three  feet  in  diameter  and  five  feet  high, 
able  to  hold  seven  hundred-weight  of  iron.  He  bought  a 


46  MODERN  SCIENCE  READER 

powerful  air  engine  and  ordered  in  a  quantity  of  crude 
iron.  This  was  at  Baxter  House,  a  place  to  be  ever  memo- 
rable in  the  history  of  the  steel  trade.  The  apparatus  was 
ready,  the  engine  was  forcing  streams  of  air  into  the  open- 
ings in  the  fireclay-lined  vessel,  and  the  stoker  was  told  to 
pour  in  the  iron  as  soon  as  it  was  sufficiently  melted. 

The  metal  was  turned,  and  a  volcanic  eruption  ensued; 
such  a  blaze  of  dazzling  fire  was  never  seen  in  a  workshop 
before.  Coruscations  of  fire  filled  the  chamber.  The 
metal  flowed  down,  and  the  air  burst  through  it  upward, 
breaking  away  in  great  bubbles  of  living  glory.  A  pot-lid 
hanging  over  the  blaze  disappeared  in  the  flame.  All  this 
time  the  air  was  rushing  into  the  molten  mass,  and  no  one 
dared  go  near  to  shut  it  off.  While  they  were  debating 
the  flame  died  down.  Soon  the  result  of  this  wonderful 
pyrotechnic  could  be  examined.  It  was  steel!  Seven 
hundred-weight  of  steel  made  from  melted  pig  without 
crucible,  coke  dust,  orv  charcoal.  Seven  hundred-weight  of 
steel  born  simply  of  fire  and  air  I1 

The  British  Association  met  in  the  following  week,  and 
Bessemer  read  a  paper  describing  his  process,  exhibiting  at 
the  same  time  his  results.  It  was  on  the  eleventh  day  of 
August,  1856,  that  this  public  announcement  was  made  of 
the  new  method.  The  whole  industrial  world  was  aroused 
by  the  tidings.  Bessemer 's  paper  was  reproduced  in  the 
Times,  and  the  iron  trade  examined  the  discovery  with 
infinite  interest.  Experiments  were  made  in  a  great  many 
foundries,  and  the  sole  talk  of  the  hour  was  the  new  way 
of  making  steel.  Within  three  weeks  after  reading  his 
paper  at  Cheltenham,  Bessemer  had  sold  £25,000  of  licenses 
to  manufacture  under  his  patent.  The  Dowlais  Iron  Com- 
pany was  the  first  to  begin  the  manufacture.  Bessemer 
personally  directed  the  construction  of  the  works.  Again 
the  molten  iron  was  poured  into  the  receptacle,  again  the 
air  blast  bubbled  through  the  metal,  the  gorgeous  display 

'See  Fig.  2  in  the  article  "The  Anatomy  of  a  Steel  Kail,"  which 
illustrates  a  modern  Bessemer  converter  in  blast. 


CREATORS  OF  THE  AGE  OF  STEEL    47 

of  Baxter  House  was  repeated,  everything  went  well,  but 
the  result  was  not  steel — it  was  nothing  but  a  very  good 
cast  iron. 

Those  who  had  praised  the  new  process  now  ridiculed  it. 
The  failure  was  inexplicable,  but  it  was  a  failure,  and 
exactly  six  weeks  after  the  publication  of  the  article  in  the 
Times  a  meeting  of  iron  masters  at  Dudley  condemned  the 
Bessemer  process  as  a  practical  failure. 

The  inventor  was  not  dismayed.  Patiently  and  hope- 
fully he  set  to  work  to  find  the  flaw  that  had  spoiled  his 
work.  A  long  series  of  experiments  followed  before  he 
found  the  cause  of  his  failure.  By  a  mere  chance  the  iron 
used  on  the  occasion  at  Baxter  House  when  steel  was  made 
was  Blaenavon  pig,  which  was  exceptionally  free  from 
phosphorus.  The  metal  used  at  the  Dowlais  works  con- 
tained this  element.  Here  he  found  the  cause  of  his  fail- 
ure. He  set  to  work  to  eliminate  the  phosphorus  by  the 
puddling  process,  but  while  doing  this  there  arrived  an 
invoice  of  Swedish  pig  iron,  clear  of  the  obnoxious  sub- 
stance. Under  his  original  process  this  yielded  steel  of 
such  a  high  quality  that  he  at  once  abandoned  the  effort 
to  dephosphorize  ordinary  iron,  and  began  to  manufacture 
from  the  Swedish  import.  Sheffield  steel  was  selling  at 
£60  per  ton ;  he  could  buy  Swedish  pig  for  £7,  and  turn  it 
into  steel  at  a  very  small  cost. 

Steel  is  pure  iron  with  a  small  percentage  of  carbon  to 
harden  it.  The  line  of  demarcation  between  steel  and 
iron  is  a  difficult  one  to  trace.  Following  the  discoveries 
made  in  India  by  J.  M.  Marshall,  Bessemer  introduced 
ferro-manganese  into  his  converter,  and  the  pure  iron  was 
at  once  carburized  into  steel. 

The  public,  however,  had  lost  confidence  in  Bessemer; 
he  had  spent  his  private  fortune,  he  had  made  steel,  the 
point  was  now  to  sell  that  steel.  Through  the  assistance 
of  Mr.  Galloway,  Bessemer  bought  in  the  licenses  which  he 
had  sold,  works  were  erected,  and  steel  produced  at  a 
profit  at  £42  a  ton— Sheffield  was  selling  at  £60.  This 


48  MODERN  SCIENCE  READER 

argument  was  unanswerable— the  Bessemer  process  had 
won,  the  ironmasters  took  out  licenses  under  it,  and  the 
age  of  steel  began. 

The  revolution  spread  over  Europe  and  America;  the 
process  was  especially  popular  in  Sweden,  where  the  Crown 
Prince  superintended  its  first  trial.  In  Prussia  Herr 
Krupp,  the  great  cannon  maker,  agreed  to  pay  Bessemer 
£5,000  for  a  license.  With  Bessemer 's  papers  Krupp  ap- 
plied to  the  Government  for  a  patent,  the  patent  was 
refused,  and  no  royalty  was  ever  paid  to  the  inventor. 
Belgium  and  France  appropriated  the  new  process,  and 
declined  to  recognize  Bessemer. 

Bessemer  had  attacked  the  problem  of  making  steel  for 
the  purpose  of  having  a  better  gun-metal  than  any  then 
existing.  Accordingly  he  returned  to  his  experiments  with 
ordnance.  Steel  cannon  were  cast  with  a  tensile  strength 
of  thirty  tons  to  the  square  inch,  figures  much  greater  than 
had  been  reached  before.  A  number  of  tests  were  ordered 
at  Woolwich,  but  through  rank  favoritism  the  matter  was 
submitted  to  Sir  William  Armstrong,  a  rival  cannon  maker, 
and  very  naturally  an  adverse  decision  was  rendered.  The 
Government  would  not  touch  the  new  metals,  and  Bessemer, 
for  the  time  being,  let  the  matter  pass,  concentrating  his 
attention  upon  the  industrial  uses  of  steel,  a  field  large 
enough  for  the  ambition  of  any  man.  In  1861  he  induced 
the  London  and  Northwestern  Railroad  to  put  down  some 
steel  rails  as  an  experiment.  In  1881  these  rails  were  still 
in  good  condition— iron  rails  had  to  be  turned  once  in  nine 
months.  The  next  step  was  the  substitution  of  steel  for 
iron  in  ship-building;  the  next,  an  invention  of  steel  pro- 
jectiles, which  were  found  to  penetrate  the  iron  armor  of 
ships  as  easily  as  the  old  iron  balls  went  through  wooden 
vessels.  At  this  time  Bessemer  was  receiving  £100,000  a 
year  from  his  business,  but  his  inventive  faculty  did  not 
lie  dormant.  The  best  known  of  his  later  devices  was  a 
ship  built  with  an  automatically  balanced  cabin  in  order 
to  do  away  with  sea-sickness.  This  was  a  theoretical  sue- 


CREATORS  OF  THE  AGE  OF  STEEL     49 

cess,  but  a  practical  failure.     Henry  Bessemer 's  life-work 
was  the  production  of  steel  from  cast  iron;  all  the  other 
many  achievements  of  his  mind  were,  after  all,  but  side 
issues.     In  the  first  twenty  years  of  the  life  of  his  inven- 
tion he  had  saved  to  the  industry  of  the  world  over  a 
billion  pounds  sterling— that  is,  the  work  of  one  man  did 
nearly  twice  as  much  to  build  the  wealth  of  the  world  as 
the  American  civil  war  did  to  pull  it  down— indeed,  figur- 
ing upon  the  actual  saving  made,  Bessemer 's  invention  had 
saved  enough  money  to  humanity  by  1882  to  pay  for  the 
American  civil  war,  the  Franco-Prussian  war,  the  Austro- 
Prussian  war,  and  the  Italo-Franco-Austrian  war  of  1859. 
The  inventor  had  been  made  a  knight  of  the  Order  of 
Francis  Joseph,  he  had  been  given  the  Grand  Cross  of  the 
Legion  of  Honor,  but  the  British  Government  declined  to 
permit  him  to  accept  it.     Out  of  the  enormous  benefits  of 
his  invention  there  has  come  to  the  inventor  a  fortune  for 
himself.     When  his  patent  expired  in  1870,  he  had  been 
paid  in  royalties  £1,057,748.     Added  to  this,  his  Sheffield 
works  divided  in  profits  during  their  fourteen  years'  exist- 
ence fifty-seven  times  the  original  capital,  and  the  works 
sold  for  twenty-four  times  the  original  capital.     In  1879 
Bessemer  was  knighted  by  the  Queen;  honors  were  show- 
ered upon  him.     His  services  to  humanity  were  recognized 
at  home  and  abroad.     All  of  the  great  cities  of  Europe 
conferred  their  freedom  upon  him,  and,  what  caused  the 
utmost  pleasure  to  the  inventor,  a  town  in  Indiana  whose 
chief  industry  was  based  upon  his  invention  was  named 
for  him,  assuring  him  the  only  immortality  that  he  desires 
—the  constant  record  of  his  memory  among  the  men  for 
whom  he  worked. 

SIR  WILLIAM  SIEMENS.— Next  to  Sir  Henry  Bessemer 
among  the  creators  of  the  age  of  steel  stands  Sir  Charles 
William  Siemens,  who  was  the  philosopher  of  the  new  era, 
as  Bessemer  was  the  inventor.  After  becoming  a  thorough 
student  in  electricity,  Siemens'  first  exploit  which  attracted 
general  attention  was  the  invention  with  his  brother  of  the 
4 


50  MODERN  SCIENCE  READER 

system  of  anastatic  printing,  a  process  by  which  any  old 
or  new  printed  matter  could  be  reproduced.  This  was 
rather  a  success  d'estime  than  a  money-making  discovery, 
although  it  brought  the  young  inventors  into  European 
notoriety.  The  method  consists  in  applying  caustic  baryta 
to  a  page  of  printed  matter,  changing  the  ink  to  a  non- 
soluble  soap,  and  then  applying  sulphuric  acid  to  precipi- 
tate the  stearine.  The  paper  was  then  pressed  into  a  slab 
of  zinc,  making  an  intaglio  from  which  copies  could  be 
easily  taken. 

Siemens  next  perfected  a  method  for  greatly  increasing 
the  heating  power  of  furnaces  by  compressed  air,  the  results 
being  of  immense  practical  value  to  the  trade.  The  very 
high  temperature  which  he  was  thus  able  to  gain  at  a  small 
cost  of  fuel  naturally  was  applied  to  the  working  of  steel. 
His  method  is  called  the  "open  hearth  process."  In  this 
process  the  charge  consists  of  pig  iron,  which  is  placed  on 
the  bottom  and  around  the  sides  of  the  furnace.  Melting 
requires  four  or  five  hours,  then  pure  ore  is  charged 
cold  into  a  bath  in  quantities  of  four  and  five  hundred- 
weight. Violent  ebullition  ensues,  and  when  this  ceases 
more  ore  is  put  in,  the  object  being  to  keep  the  boiling 
uniform.  Spiegeleisen  or  ferro-manganese  is  added,  and 
the  charge  is  cast.  The  result  is  steel.  Siemens'  first  im- 
provement was  a  rotating  furnace,  in  which  coal  and  iron 
are  put  together,  and  mixed  and  heated  so  thoroughly  that 
the  result  is  all  that  could  be  desired.  So  thorough  is  the 
process  that  the  hitherto  irreducible  iron-sands  of  New 
Zealand  and  Canada  can  be  worked  to  a  great  profit. 

Coming  into  direct  competition  with  the  Bessemer  prod- 
uct, the  open-hearth  steel  has  held  its  own,  its  consumption 
in  the  United  Kingdom  rising  from  77,500  tons  in  1873  to 
436,000  in  1882.  The  Lindore-Siemens  Company  rolls  the 
armor-plate  for  the  British  Admiralty,  and  the  steel  has 
been  found  to  be  even  better  than  the  Bessemer  for  general 
ship-building.  In  1883  one  fourth  of  the  total  tonnage  of 
new  ship-building  was  built  of  Siemens  steel. 


CREATORS  OF  THE  AGE  OF  STEEL     51 

Sir  William  Siemens  and  his  brother,  Dr.  Ernst  Werner 
Siemens,  of  Berlin,  have  been  called  the  pioneers  of  modern 
electrical  research.  The  dynamo  machine  is  theirs,  and 
much  of  the  development  of  the  electric  light.  Siemens 
has  put  on  record  a  series  of  experiments  in  electrohorti- 
culture  which  show  astonishing  results.  In  the  hostile 
English  climate  he  has  produced  ripe  peas  by  the  middle 
of  February,  raspberries  on  March  1st,  strawberries  Feb- 
ruary 14th,  grapes  March  10th ;  bananas  and  melons  showed 
similar  results. 

The  German  electric  railway  is  one  of  the  enterprises  of 
the  Siemens.  They  are  the  builders— the  creators— of  the 
Indo-European  telegraphs,  reaching  from  London  to  Te- 
heran, in  Persia.  The  history  of  this  enterprise,  with  its 
dangers  braved  and  its  difficulties  overcome,  is  one  of  the 
most  interesting  of  this  interesting  book. 

The  Siemens  laid  the  first  submarine  cable  in  1847  from 
Deutz  to  Cologne,  covering  their  wires  with  gutta  percha. 
The  services  of  Sir  William  Siemens  to  science  as  well  as 
to  the  useful  arts  cannot  be  too  highly  appreciated.  Be- 
sides his  industrial  triumphs,  he  constructed  our  theory 
of  heat.  Wealth  and  honors  came  to  him,  but  in  the  midst 
of  his  career  he  was  cut  down.  An  accidental  fall  on  a 
London  pavement,  November  5,  1883,  ruptured  the  nerves 
of  his  heart,  and  he  died  a  fortnight  later,  his  death  being 
mourned  as  a  national  loss  in  England  and  Germany. 

SIR  JOSEPH  WHIT  WORTH.— Joseph  Whitworth's  first  in- 
dustrial exploit  was  the  production  of  true  plane  surfaces 
in  metals  automatically,  an  achievement  perfected  in  1840. 
The  old  method  was  grinding  with  emery  powder  and 
water.  He  planed  the  metals  with  a  steel  plane.  "So 
exactly  can  surface  plates  be  made  by  his  apparatus,  that  if 
one  of  them  be  placed  upon  another,  when  clean  and  dry, 
the  upper  will  seem  to  float  upon  the  under,  without  being 
actually  in  contact  with  it,  the  weight  of  the  upper  plates 
being  insufficient  to  expel  except  by  slow  degrees  the  thin 
film  of  air  between  their  surfaces.  But  if  the  air  be  ex- 


52  MODERN  SCIENCE  READER 

pelled  the  plates  will  adhere  together,  so  that  by  lifting  the 
upper  one  the  lower  will  be  lifted  along  with  it,  as  if  they 
formed  one  plate." 

Whitworth  was  essentially  a  tool  maker.  No  sooner  had 
he  perfected  the  plane,  with  its  immense  effect  upon  Eng- 
lish industry,  than  he  attacked  the  screw.  His  system  of 
screws  is  now  adopted  all  over  the  civilized  world.  Follow- 
ing up  his  improvements,  he  recognized  the  necessity  for  a 
more  exact  measuring  machine  than  any  then  in  existence, 
and  supplying  this  want  he  devised  a  machine  which  would 
measure  distinctly  and  practically  to  the  40,000th  part  of 
an  inch,  and  theoretically  to  the  1,000,000th.  To  show  to 
what  exactness  this  was  brought,  we  quote  his  own  words 
in  an  address  at  Manchester  in  1857 :  ' ' Here, ' '  said  he,  "is 
an  internal  gauge  having  a  cylindrical  aperture  0-5770-inch 
diameter,  and  here  also  are  two  solid  cylinders,  one  0-5769- 
inch,  and  the  other  0-5770-inch  diameter.  The  latter  is 
0-0001  of  an  inch  larger  than  the  former,  and  fits  tightly 
in  the  internal  gauge  when  both  are  clean  and  dry,  while 
the  smaller  0-5769  gauge  is  so  loose  in  it  as  not  to  appear 
to  fit  at  all.  These  gauges  are  finished  with  great  care, 
and  are  made  true  after  being  case-hardened.  The  effect 
of  applying  a  drop  of  fine  oil  to  the  surface  of  this  gauge 
is  remarkable.  It  will  be  observed  that  the  fit  of  the  larger 
cylinder  becomes  more  easy,  and  that  of  the  smaller  more 
tight.  ...  It  is  thus  obvious  to  the  eye  and  the  touch  that 
the  difference  between  these  cylinders  of  one  ten-thousandth 
of  an  inch  is  an  appreciable  and  important  quantity,  and 
what  is  now  required  is  a  method  which  shall  express 
systematically  and  without  confusion  a  scale  applicable  to 
such  minute  differences  of  measurement."  The  Whit- 
worth  gauges  have  been  adopted  by  the  Government  as 
standards  of  measurement. 

The  accuracy  in  mechanical  processes  rendered  possible 
by  Whitworth 's  inventions  bore  its  first  proof  in  a  direction 
which  the  inventor  little  expected. 

England  was  engaged  in  the  Crimean  war,  and  the  En- 


CREATORS  OF  THE"  AGE  'OF  STEEL  53 

field  rifle,  a  hand-made  weapon,  was  the  arm  of  her  forces. 
It  became  necessary  to  have  these  guns  in  large  quantities, 
and  the  burning  question  of  the  hour  was  how  to  make  these 
rifles  by  machinery.  The  science  of  projectiles  was  then 
entirely  empiric.  Some  guns  shot  well  and  some  shot  ill, 
but  why  these  were  good  and  those  bad  no  one  knew. 
Whitworth  went  before  a  Parliamentary  committee,  and 
told  it  that  until  the  data  of  rifling  were  established  good 
machine  made  guns  would  be  impossible.  It  was  necessary 
to  find  out  what  made  an  effective  gun  by  continued  exper- 
iment before  anything  else  was  done. 

England  needed  a  million  rifles.  To  make  these  by  the 
processes  then  in  use  would  have  taken  Birmingham  twenty 
years.  It  was  agreed  that  the  Government  should  bear  the 
expenses  of  Whitworth 's  experiments. 

A  gallery  was  set  up  at  Rusholme,  500  yards  long,  fur- 
nished with  tissue  paper  screens  in  order  to  track  the  bul- 
lets throughout  their  flight,  and  with  sliding  targets.  The 
experiments  began  in  March,  1855.  The  Enfield  rifle  had 
a  bore  of  0-577-inch,  and  the  rifling  had  one  turn  in  78 
inches.  The  first  result  was  that  in  every  particular  the 
Enfield  was  found  to  be  wrong.  Whitworth  made  barrels 
with  one  turn  in  60  inches,  one  in  30,  one  in  20,  one  in  10, 
one  in  5,  and  one  in  1  inch.  To  be  brief,  he  determined 
conclusively  that  the  best  rifle  had  one  turn  in  20  inches, 
a  minimum  diameter  of  45  inches,  and  a  rounded  hexagonal 
instead  of  a  circular  bore.  After  beating  all  other  guns  at 
short  ranges  the  Whitworth  rifle  had  a  deviation  of  about 
4-62  feet  at  1,400  yards.  The  Enfield  could  not  hit  the 
target  at  all.  With  a  steel  bullet  Whitworth 's  rifle  per- 
forated plates  of  iron  half  an  inch  thick  at  an  obliquity  of 
fifty  degrees,  and  easily  passed  through  thirty-four  half- 
inch  elm  boards. 

Applying  the  same  principles  to  artillery,  Whitworth 
devised  a  gun  which  threw  two  and  one-fourth  hundred- 
weight of  iron  six  and  a  half  miles. 

To  such  a  great  superiority  did  he  bring  artillery,  first 


54  MODERN  SCIENCE  READER 

by  his  invention  of  compressed  steel,  next  by  making  the 
guns  breech-loading,  and  finally  by  increasing  the  size  of 
the  powder  chamber,  that  it  began  seriously  to  be  doubted 
whether  any  armor  could  be  made  able  to  resist  the  crush- 
ing force  of  the  square-headed  Whitworth  projectiles. 
Whitworth  himself  attacked  the  new  problem,  and  in  1877 
prevailed.  He  made  plates  of  compressed  steel,  built  in 
hexagonal,  each  of  which  was  composed  of  a  series  of  con- 
centric rings  around  the  central  disk.  The  rings  prevented 
the  spreading  of  a  crack  beyond  the  one  in  which  it 
occurred.  Of  this  material  a  target  was  composed  nine 
inches  thick,  supported  by  a  wood  backing  against  a  sand 
bank.  In  front  a  horizontal  iron  tube  was  put  to  receive 
the  fragments  of  the  shot.  Against  this  target  a  Palliser 
shell  weighing  250  pounds  was  fired  point  blank  from  a 
nine-inch  gun,  with  fifty  pounds  of  pebble  powder,  at  a 
distance  of  thirty  yards.  This  shell  would  have  passed 
through  twelve  inches  of  ordinary  armor;  against  the  new 
target  it  was  shattered  into  innumerable  fragments.  The 
target  was  drawn  back  eighteen  inches  into  the  sand.  The 
fragments  of  the  projectile,  escaping  at  the  end  of  the 
tube,  continued  their  rotation  in  such  a  manner  as  to  cut 
through  the  planks  in  front  of  the  displaced  target.  The 
only  piece  that  survived  the  shock  was  a  flattened  mass  of 
eight  pounds,  formed  from  the  apex  of  the  shell  and  left 
embedded  in  the  target,  where  it  had  made  an  excavation 
of  eight  inches  in  diameter,  and  four  tenths  of  an  inch 
deep  in  the  deepest  part.  The  ring  which  received  the 
shot  was  not  cracked. 

This  experiment  alone  effected  a  revolution  in  naval 
armament. 

There  is  not  room  here  to  speak  of  Sir  Joseph  Whit- 
worth 's  eminent  services  to  the  cause  of  technical  educa- 
tion. He  has  devoted  a  large  part  of  the  great  fortune 
won  by  his  inventive  genius  to  the  founding  of  schools  and 
scholarships  for  the  benefit  of  young  men  desiring  to  ex- 
plore the  wide  field  of  mechanical  industry. 


CREATORS  OF  THE  AGE  OF  STEEL     55 

SIDNEY  GILCIIRIST  THOMAS.— It  will  be  remembered  that 
the  Bessemer  process  failed  after  its  first  success,  and  that 
the  reason  of  that  failure  was  the  presence  of  phosphorus 
in  the  pig  iron.  Such  an  insuperable  obstacle  did  this 
present  that  Bessemer  gave  up  the  problem,  and  went  to 
Sweden  for  his  pig.  To  Mr.  Sidney  Gilchrist  Thomas  be- 
longs the  honor  of  discovering  a  means  of  getting  rid  of 
this  obnoxious  element.  Acting  upon  his  idea,  he  and  his 
cousin  Mr.  Gilchrist,  the  first  twenty-six,  the  latter  twenty- 
five  years  old,  conducted  an  exhaustive  series  of  experi- 
ments to  find  a  base  with  which  phosphorus  would  unite. 
A  base  is  the  name  given  in  chemistry  to  any  element  for 
which  an  acid  has  affinity.  At  last  they  made  bricks  of 
lime  and  magnesia,  which  they  subjected  to  an  intense 
white  heat,  when  they  became  hard  as  flint.  With  these 
bricks,  which  were  a  base,  they  lined  their  converters,  the 
melted  pig  iron  was  poured  in,  and  the  phosphorus  at  once 
left  the  metal  and  attached  itself  to  the  bricks.  A  quantity 
of  lime  is  added  to  the  run,  and  the  result  is  a  thoroughly 
dephosphorized  iron. 

The  news  of  the  new  process  spread  through  Europe,  and 
to  show  how  greatly  the  invention  was  appreciated,  the 
following  circumstance  is  detailed:  A  continental  iron 
master  called  on  Mr.  Thomas  at  7 :30  one  April  morning  to 
arrange  for  terms  for  the  use  of  the  patent.  Just  as  they 
were  concluded,  a  telegram  was  handed  to  Mr.  Thomas, 
stating  that  another  iron  master  from  the  same  district  was 
coming  to  arrange  terms.  The  first  visitor  had  secured  a 
monopoly,  and  the  second  man  was  too  late.  Both  of  the 
iron  men  had  come  over  on  the  same  boat ;  one  had  driven 
straight  to  the  patentee  on  landing,  the  other  had  gone  to 
get  his  breakfast. 

Before  the  process  was  three  years  old  it  was  the  means 
of  producing  half  a  million  tons  of  steel  per  annum. 


THE  ANATOMY  OF  A  STEEL  RAIL1 

BY   HENEY  COOK   BOYNTON,    S.   D. 

Metallurgist  for  J.  A.  Roebling's  Sons   Co. 

WHO  would  ever  think,  to  look  at  a  dull  fragment  of  iron 
or  steel,  that  such  a  piece  of  metal  had  an  internal  history ! 
But  if  this  same  inert,  apparently  insensible,  piece  of  metal 
be  polished  and  suitably  prepared  for  examination  under 
a  microscope,  its  internal  structure  is  more  clearly  and 
surely  shown  than  is  the  interior  skeleton  of  a  man  by  the 
X-ray. 

However  shapeless  or  structureless  this  piece  of  iron  or 
steel  seems  to  be,  it  is  now  perfectly  easy  to  show  by  a 
proper  treatment  what  the  metal  is  composed  of,  how  it 
was  treated,  and  what  makes  it  good  or  bad ;  in  fact  its 
entire  "family  skeleton"  can  be  exposed  with  the  greatest 
of  ease.  If  it  was  created  good,  and  has  since  degenerated 
through  hard  usage  or  abuse,  or  if  it  was  predestined  to  be 
bad  all  its  life,  these  properties  and  a  great  many  more 
can  be  shown  with  an  ordinary  compound  microscope. 

It  was  only  a  few  years  ago  that  any  intelligent  engineer 
would  have  said,  ' '  If  you  will  tell  me  the  chemical  composi- 
tion of  your  metal,  I  will  tell  you  whether  it  is  of  good  or 
bad  quality."  This  statement  has  been  lately  proved  to  be 
absurd.  He  might  just  as  well  have  said,  "If  you  will  tell 
me  how  much  carbon,  oxygen,  hydrogen,  nitrogen,  etc., 
there  is  in  a  certain  man's  body,  I  can  tell  you  if  he  is  a 
good  healthy  fellow." 

Many  times  lately  has  the  engineer's  statement  been  dis- 
proved. A  boiler  explodes  and  scalds  many  men ;  an 
apparently  sound  rail  breaks  under  the  load  of  the  "Light- 

1  Published  in  Harper's  Monthly  Magazine  for  March,  1906.  Copy- 
right, 1906,  by  Harper  and  Brothers. 

56  ' 


THE  ANATOMY  OF  A  STEEL  RAIL  57 

ning  Express"  and  people  are  hurled  to  destruction;  yet 
chemical  analysis  alone  of  the  defective  metals  used  showed 
them  to  have  been  apparently  reputable ;  they  had  the 
requisite  amounts  of  carbon,  manganese,  and  silicon,  and 
not  too  much  sulphur  or  phosphorus,  but  just  like  many  a 
person  who  mingles  with  his  associates  for  years,  and  some 
day  suddenly  is  found  to  be  "bad,"  so  did  these  metals 
outwardly  and  inwardly,  as  far  as  the  chemist  was  con- 
cerned, appear  to  be  fulfilling  their  duties  as  respectable 
adjuncts  to  our  civilization. 

But  take  the  bad  boiler-plate  or  the  defective  rail  and 
prepare  it  for  examination  under  the  microscope,  and  the 
whole  reason  for  its  failure  to  do  its  duty  becomes  as  clear 
to  the  trained  metallurgist  as  that  the  arsenic  which  the 
chemist  finds  in  the  stomach  of  the  lifeless  patient  was  the 
cause  of  his  death. 

To  elaborate  a  little  farther,  let  us  take  a  steel  rail,  a 
plain  every-day  steel  rail  such  as  is  used  on  all  our  rail- 
roads to  hold  up  the  daily  loads  of  human  beings  and 
freight  transported  from  one  place  to  another.  This  rail 
is  the  band  which  joins  one  state  to  another,  the  East  with 
the  West,  and  one  country  with  its  neighbor.  This  rail 
was  shaped  from  a  huge  white-hot  piece  of  steel  by  being 
passed  successively  through  properly  shaped  rolls.  Sup- 
pose we  saw  out  of  the  center  of  this  rail  a  small  specimen, 
about  a  one-half  inch  cube,  and  explain  how  it  may  be 
treated  to  bring  forth  its  internal  skeleton. 

After  cutting  out  our  specimen  with  a  steel  saw,  the 
piece  must  be  ground  to  a  plane  surface  on  an  emery 
wheel,  given  a  second  and  smoother  finish  on  another  wheel 
fed  with  flour-emery,  lastly  receiving  its  final  polish  on  two 
wooden  wheels  covered  with  the  finest  and  smoothest  broad- 
cloth and  fed  respectively  with  a  paste  of  tripoli  and  rouge 
powder.  This  whole  operation  of  polishing,  when  done  by 
an  expert,  occupies  only  about  fifteen  minutes. 

Emerging  from  the  rouge  treatment,  the  metal  stands 
forth  in  its  best  clothes,  with  not  a  spot  or  scratch  to  mar 


58  MODERN  SCIENCE  READER 

its  silvery-white  and  mirror-like  face.  Like  the  ordinary 
workingman  with  his  overalls  off,  a  clean  shave,  and  his 
best  clothes  on,  you  would  hardly  recognize  the  plain 
ordinary  workaday  steel  rail  with  its  old  coat  of  brown  or 
black. 

But  some  one  may  ask,  "Why  do  we  seldom  see  steel 
with  this  silver- white  color?"  We  do  occasionally,  as  in 
razors,  knives,  etc.,  but  ordinarily  the  moisture  in  the  air 
so  quickly  attacks  such  a  polished  surface  that  if  unpro- 
tected it  speedily  gains  a  coat  of  iron  oxide  or  rust.  A 
metallurgist  keeps  all  his  polished  specimens  of  iron  or 
steel  in  a  desiccator,  a  receptacle  which  is  kept  free  from 
moisture  by  some  chemical  that  absorbs  water,  and  in  this 
way  the  prepared  faces  keep  bright  and  untarnished  for 
months  and  sometimes  years. 

Before  the  highly  polished  steel  is  ready  to  be  photo- 
graphed, it  must  be  treated  so  as  to  make  visible  under  the 
microscope  just  what  its  interior  architecture  really  is. 

The  treatment  consists  simply  in  subjecting  our  piece  of 
rail  to  the  action  of  some  reagent,  some  chemical  compound, 
or  to  any  treatment  which  will  attack  the  different  com- 
ponents of  our  metal  to  a  different  degree,  and  which  will 
make  each  one  stand  out  plainly  from  his  fellows.  Such 
a  treatment  is  generally  an  "etching,"  and  in  the  case  of 
our  steel  rail  we  immerse  it  for  a  few  seconds  in  a  solution 
of  nitric  acid  and  alcohol.  The  acid  first  attacks  the  junc- 
tions of  the  different  grains  in  the  metal,  then  the  grains 
themselves,  coloring  some  brown  or  black,  but  leaving  others 
white.  Then  our  rail  stands  out  in  its  true  colors;  it  has 
lost  some  of  its  previous  polish,  but  its  whole  true  frame- 
work, its  structure,  lies  plainly  before  us.  But  to  the 
ordinary  observer  the  polished  surface  of  the  metal  shows 
practically  no  change;  its  polish  is  a  little  less  brilliant, 
and  only  a  slight  grayish  appearance  is  visible  to  the 
unaided  eye. 

"How  then,"  says  the  layman,  "can  you  tell  if  that  was 
a  good  or  a  bad  rail?"  Then  comes  the  microscope,  that 


THE  ANATOMY  OF  A  STEEL  RAIL  59 

simple  instrument  which  has  revealed  so  many  wonders. 
It  enables  the  expert  physician  to  tell  the  difference  between 
the  blood  of  a  human  being  and  that  of  other  animals ;  the 
mineralogist,  to  discriminate  between  very  minute  particles 
of  quartz  or  diamond ;  the  zoologist,  to  watch  the  embryonic 
development  of  the  starfish ;  and  it  now  permits  the  metal- 
lurgist to  study  the  anatomy  of  so  apparently  lifeless  a 
thing  as  a  piece  of  steel. 

With  a  vertical  illuminator,  or  kind  of  reflector  which 
takes  the  light  rays  from  any  source  and  bends  them 
through  a  right  angle,  and  then  permits  the  observer  to 
look  through  it  down  on  to  the  polished  surface  of  metal- 
equipped  with  such  a  reflector  attached  to  an  ordinary 
microscope,  and  with  a  number  of  different  lenses  called 
objectives  and  eyepieces,  the  metallurgist  can  look  at  his 
piece  of  rail  under  a  linear  magnification  of  forty  to  a 
thousand  diameters.  This  means  that  if  a  spot  measuring 
one  hundredth  of  an  inch  across  be  magnified  one  hundred 
diameters,  the  original  spot  would  appear  to  the  eye  of  the 
observer  one  inch  in  diameter. 

Can  you  conceive  of  anything  in  that  rail  that  could 
escape  the  trained  eye  when  under  a  magnification  of  one 
thousand  diameters?  It  would  have  to  be  more  elusive 
than  the  tiny  germs  which  medical  men  look  for  as  the 
cause  of  most  of  our  contagious  diseases,  than  the  500,000 
bacteria  in  a  cubic  centimeter  of  the  ordinary  milk  we 
drink. 

By  throwing  the  structure  which  we  see  under  the 
microscope  upon  a  ground  glass  in  a  special  camera,  and 
then  substituting  a  photographic  plate  for  the  ground  glass, 
a  picture  can  be  obtained  in  the  usual  way  of  photography. 
Such  a  portrait  of  our  rail  may  be  seen  in  Fig.  1,  which  is 
a  fair  average  sample  of  a  good  steel  rail. 

By  examining  this  picture  a  little  more  closely,  we  notice 
light  and  dark  areas;  the  former  are  the  pure  iron  grains, 
or  ferrite,  as  the  metallurgist  calls  them,  and  the  latter 
"pearlite,"  because  it  looked  like  mother-of-pearl  to  the 


60  MODERN  SCIENCE  READER 

person  who  first  discovered  it.  The  ferrite  makes  the  rail 
tough  to  resist  fracture,  and  the  pearlite  is  the  part  of  the 
metal  which  contains  the  carbon  and  which  makes  the  rail 
hard  and  stronger  than  iron  and  enables  it  to  wear  well 
under  the  friction  of  the  car  wheels.  The  metallurgist  at 
a  glance  knows  this  to  be  the  normal  structure  of  a  good 
steel  rail  such  as  daily  and  hourly  fulfils  its  duty  all  over 
the  world. 

But  let  us  return  to  the  rail  which  broke,  which  could 
not  stand  the  speed  of  the  express  train.  This  rail  out- 
wardly had  the  appearance  of  respectability;  the  section 
boss  had  tested  it  with  his  sledge  many  times ;  it  had  held 
up  bravely  under  many  a  train;  but  suddenly  it  "went 
bad." 

A  good  steel  rail  on  the  open  road  will  stand  at  least  ten 
years  of  active  service,  years  during  which  the  swiftest 
passenger  trains  with  the  heaviest  of  all  cars,  the  "Pull- 
mans," go  pounding  across  the  joints.  The  freight  trains 
with  their  more  ponderous  engines  and  more  heavily  loaded 
cars  seldom  break  a  rail,  on  account  of  their  much  slower 
rate  of  speed ;  for  the  ordinary  steel  rail,  good  or  bad,  will 
sustain  ten  times  the  load  put  upon  it  if  this  be  applied 
slowly;  but  the  high  speed  of  the  heavy  passenger  train  is 
apt  to  make  the  bad  rail  succumb  to  the  sudden  shock  of 
the  gigantic  monster  which  hammers  down  upon  it. 

The  rail  which  is  put  in  a  critical  place,  as  for  example 
on  a  very  sharp  curve,  is  seldom  found  wanting,  for  the 
very  reason  that  only  the  best  selected  stock  is  used  for 
such  a  locality,  and  a  dangerous  curve  is  always  assidu- 
ously watched  by  the  section  man  and  the  division  super- 
intendent. 

The  faulty  rail,  however,  on  the  straight  track,  which 
got  slipped  in  with  the  good  ones,  is  the  one  to  be  dreaded, 
for  after  leaving  the  mill  there  is  no  possible  way  to 
distinguish  this  physically  incompetent  piece  of  steel  from 
its  good  neighbors. 

For  a  better  understanding  of  some  of  the  imperfections 


FIG.  1. — STEEL  BAIL  OF  GOOD  QUALITY, 
MAGNIFIED  100  DIAMETERS.  ROLLING 
FINISHED  AT  THE  RIGHT  TEMPERATURE 


•  •  •  "•'«.*•"•».*  •»  *t;' ;:#*•;$*  £>,*:.«**•  >'*-*>'*:f^ ,''  >:  V 

*£&£  .$£••  s^Xffgsc^^*^^®  ^S 

•••.^.-/•.'"•"••^y  »'•.  >.y-'»V»;'«V:--  •'  ,«<-;«".>**^^a>**  •-•  «*•»»»••>«••-.  '*»>*4»««»«y«»'.>^ 
C  A 


C  A 

FIG.  3. — LONGITUDINAL  SECTION  OF  STEEL  INGOT,  SHOWING  A  ' '  PIPE  ' : 
AT  C,  AND  BLOW-HOLES  AT  A  AND  B 


THE  ANATOMY  OF  A  STEEL  RAIL  61 

of  rails  let  us  digress  a  little  to  explain  the  birth  of  the 
rail.  The  steel  for  a  rail  is  made  from  a  molten  mass  of 
cast  iron,  or  pig  iron,  which  is  iron  containing  a  large 
amount  of  impurities,  the  most  notable  of  which  is  carbon. 
This  cast  iron  is  run,  white-hot  and  liquid,  from  a  blast 
furnace  into  a  Bessemer  converter,  through  the  bottom  of 
which  air  under  pressure  is  blown  in  large  quantities.  The 
impurities  in  the  pig  iron  are  burned  by  the  oxygen  in  the 
air  blast,  arid  pass  off  as  gases  or  rise  to  the  top  of  the 
refined  metal  as  slag,  essentially  a  silicate  of  iron.  Fig.  2 
is  an  illustration  of  a  Bessemer  converter  in  full  blast. 

The  whole  operation  of  converting  ten  tons  of  cast  iron 
into  steel  takes  only  about  ten  minutes,  and  when  complete 
the  molten  mass  is  made  to  absorb  the  required  amount  of 
carbon  to  give  the  necessary  strength  to  the  rail  by  adding 
spiegeleisen  or  ferro-manganese,  both  alloys  of  iron  and 
manganese  containing  carbon. 

We  now  have  a  molten  mass  of  steel,  which  is  poured 
into  iron  molds  to  solidify.  When  cool  the  molds  are 
stripped  off  and  we  have  left  large  masses  or  ingots  of 
steel,  and  this  steel  is  only  an  alloy  of  iron  and  carbon 
with  a  few  impurities  present  in  very  small  quantities. 
From  one  of  these  ingots  several  rails  may  be  made  by 
reheating  and  passing  it  through  suitably  shaped  rolls. 

I  have  shown  here  in  Fig.  3  a  diagram  of  a  longitudinal 
section  of  one  of  these  ingots.  It  is  not  at  all  homogeneous, 
as  can  readily  be  seen,  and  has  a  cavity  or  "pipe,"  above 
C,  which  is  caused  by  the  unequal  cooling  of  the  sides  and 
the  top.  The  black  spots  near  the  edge,  A  and  B,  are 
called  blow  holes  and  are  caused  by  imprisoned  gas;  they 
are  subsequently  closed  by  the  rolling,  so  that  they  are  not 
detrimental  to  the  quality  of  the  steel  rail. 

Now  this  "pipe"  cavity  should  be  all  cut  off,  as  a  rail 
which  is  rolled  from  the  end  of  the  ingot  containing  this 
pipe  is  sure  to  be  faulty,  for  it  will  always  contain  this 
cavity,  which  will  be  but  imperfectly  closed  by  the  rolling 
and  only  elongated.  To  be  absolutely  sure  that  all  the 


62  MODERN  SCIENCE  READER 

pipe  is  removed,  about  twenty  per  cent,  should  be  cut  from 
the  top  end  of  each  ingot.  Let  us  suppose,  for  sake  of 
illustration,  that  only  ten  per  cent,  is  cut  from  the  top  of 
each  ingot,  which  is  often  the  case;  a  "pipe"  rail  then 
goes  out  to  the  stock  pile  with  the  good  ones. 

But  now  suppose  we  have  before  us  a  fractured  rail 
broken  by  the  impact  of  a  heavy  train  going  at  a  high  rate 
of  speed?  Suppose  we  polish  it  and  examine  it  in  just 
the  same  way  that  we  did  our  good  rail?  What  shall  we 
find? 

We  may  find  a  partially  welded  pipe,  which,  it  goes  with- 
out saying,  is  a  source  of  weakness.  This  cavity,  which 
originated  in  our  ingot  when  rolled,  will  look  like  the  dia- 


C        a 

FIG.  4. — DIAGRAM  OF  THE  PIPE  IN  A  ' '  BLOOM,  ' '  A  PARTIALLY  BOLLED 
STEEL  INGOT 

gram  in  Fig.  4.  It  can  be  readily  seen  that  the  long  bloom, 
as  it  is  called,  should  be  cut  at  C,  and  the  butt  sent  to  be 
remelted;  but  if  cut  at  A,  the  end  of  one  rail,  just  where 
great  soundness  is  desired  (near  the  joint),  will  be  weak. 

Such  a  pipe  will  be  revealed  almost  instantly  by  etching 
a  cross  section  of  the  rail  and  examining  it  under  the 
microscope;  in  fact  in  some  cases  the  microscope  is  wholly 
superfluous,  for  the  defect  and  the  reason  for  the  disaster 
will  be  visible  to  the  naked  eye.  See  Fig.  5. 

Let  us  go  back  to  our  ingot  once  more :  at  the  foot  of  the 
pipe— the  part  which  solidifies  last,  since  top  and  sides  cool 
first— will  be  found  most  of  the  impurities  in  the  steel,  the 
most  deleterious  of  which  are  phosphorus  and  sulphur. 
Now  a  few  tenths  of  a  per  cent,  too  much  phosphorus  or 
sulphur  in  a  steel  rail  will  make  it  ''bad."  These  seem- 
ingly infinitestimal  amounts  of  sulphur  make  a  rail  snap 
suddenly  if  worked  hot;  and  worse  yet,  phosphorus  will 


FIG.   2. — TEN-TON  BESSEMER  CONVERTER  IN  FULL  BLAST,  MAKING 
TEN  TONS  OF  KAIL  STEEL  IN  TEN  MINUTES 


THE  ANATOMY  OF  A  STEEL  RAIL 


63 


cause  a  fracture  from  a  sudden  shock  when  the  metal  is 
cold.  Therefore  phosphorus  and  sulphur  are  the  evil  asso- 
ciates which  a  steel  rail  must  be  as  free  from  as  possible 
to  be'classed  as  good. 


FIG.  5. — ETCHED  SECTION  OF  A  BAD  BAIL,  SHOWING  THE  "PIPE." 
(THE  LIGHT  AREA  is  THE  EEVEALED  "PIPE") 

So,  you  see,  if  no  more  than  the  ' '  pipe ' '  be  removed,  the 
segregation  of  impurities  at  the  bottom  of  this  cavity  might 
cause  the  rail  to  snap  as  instantly  if  the  load  of  the  train 
above  hammered  down  too  suddenly  as  if  it  contained  the 
pipe.  Such  a  rail  can  generally  be  detected  only  by  the 
etching  method  and  the  microscope.  Fig.  6  shows  a  rail 
with  a  great  many  sulphur  flaws  present,  the  dark  areas 
representing  the  flaws. 


64  MODERN  SCIENCE  READER 

Moreover,  a  rail  low  in  phosphorus  or  sulphur,  which 
contains  no  traces  of  a  pipe  or  segregation,  may  prove 
defective.  The  composition  of  the  rail  is  normal.  What 
then  is  the  matter?  On  polishing  and  etching  and  exam- 
ining it  under  the  microscope  the  structure  seen  in  Fig.  7 
is  brought  to  light.  To  the  inexperienced  it  looks  all  right, 
but  to  the  steel  man  it  shows  that  the  rolling  of  the  rail  was 
finished  at  too  high  a  temperature,  that  the  grains  of  the 
steel  are  too  large,  and  long  experience  has  shown  that 
these  large  grains  produce  brittleness,  and  when  the  great- 
est toughness  combined  with  strength  is  required,  the  finest 
possible  grains  should  be  sought  for.  This  may  be  accom- 
plished by  continuing  the  rolling  down  to  a  certain  "criti- 
cal temperature,"  below  which  no  crystallization  takes 
place  when  the  rails  cool  after  rolling.  Such  a  structure 
is  seen  in  Fig.  1  and  such  a  rail  will  be  strong,  yet  tough, 
and  will  resist  sudden  shocks. 

I  do  not  intend  to  convey  the  meaning  that  the  microscope 
is  the  telescope  by  which  all  the  ills  prevalent  in  metals 
can  be  viewed  face  to  face;  but  as  used  by  the  scientific 
man,  together  with  his  indispensable  etching  compounds, 
the  microscope  is  able  in  many  cases  to  give  a  clear  clue 
to  the  sins  of  our  metals  and  their  makers. 


PIG.  6. — SECTION  OF  A  STEEL  RAIL  CON- 
TAINING TOO  MUCH  SULPHUR.  THE 
DARK  AREAS  ARE  THE  SULPHUR  FLAWS. 
MAGNIFIED  100  DIAMETERS 


PIG.  7. — STEEL  BAIL,  MAGNIFIED  100  DI- 
AMETERS. MADE  OF  GOOD  STEEL,  BUT 
ROLLING  FINISHED  AT  TOO  HIGH  A  TEM- 
PERATURE 


THE  NATURE  AND  TREATMENT  OF 
ALLOY  STEEL1 

BY  JOHN  A.  MATHEWS,   PH.   D. 

Operating  Manager,   Halcomb  Steel  Company 

PARAPHRASING  the  remark  that  has  been  made  about  books 
we  may  well  say,  of  making  many  alloys  there  is  no  end 
and  much  study  of  them  is  a  weariness  to  the  flesh  and 
small  profit  to  the  maker.  It  is  hardly  necessary  at  this 
late  day  that  an  article  upon  this  subject  should  consist  of 
long  tables  of  remarkable  physical  tests— elastic  limits 
above  100  tons,  coupled  with  the  elongation  of  molasses 
taffy  or  illustrated  with  photographs  of  steel  tied  into  bow- 
knots  and  large  forgings  distorted  in  shapes  that  would 
make  the  ''human  snake"  turn  green  with  envy.  Too 
often  in  the  past  such  data  have  raised  bright  hopes  in  the 
mind  of  a  steel  consuming  public,  and  too  often  results  in 
practice  have  fallen  short  of  published  data. 

A  few  generalizations  in  connection  with  these  recent 
fascinating  developments  in  the  steel  industry  may  serve 
a  more  useful  purpose  and  help  the  user  to  obtain  in  prac- 
tice results  equal  to  those  claimed  by  the  maker.  Let  us 
then  begin  with  the  definition  that  "steel  is  a  malleable 
alloy  of  iron  and  carbon  which  has  been  produced  by  cast- 
ing from  a  fluid  mass."  Since  by  this  definition  all  steel 
is  an  alloy,  what  is  meant  by  "alloy"  or  "special"  steels? 
AYhile  these  terms  are  in  general  well  understood,  they  are 
difficult  to  define,  though  they  may  be  described. 

Two  elements,  iron  and  carbon,  are  all  that  are  necessary 
to  produce  steel.  Four  other  elements  are  always  present 
—silicon  and  manganese,  which  are  useful  and  essential, 
and  sulphur  and  phosphorus,  impurities  whose  effects  even 

Abstracted  from  a  paper  published  in  Iron  Age,  1908. 
5  65 


66  MODERN  SCIENCE  READER 

in  homeopathic  doses  are  by  no  means  negligible.  Copper 
and  arsenic,  aluminium,  oxygen,  nitrogen,  and  cyanides  are 
usually  present  in  minute  and  negligible  quantities. 
Ordinary  steel,  by  whatever  process  made,  is  therefore  a 
wonderfully  complex  alloy,  though  often  spoken  of  as 
though  it  were  an  elemental  substance.  It  may  contain 
carbon  and  manganese  from  0.10  to  1.50  per  cent. ;  silicon 
from  0.02  to  0.25  per  cent.,  and  sulphur  and  phosphorus 
from  0.01  to  0.10  per  cent.,  and  the  other  elements  named 
above  which  are  rarely  determined.  Its  complexity  is 
further  increased  by  the  fact  that  iron  and  carbon  may 
exist  in  several  different  physical  conditions  or  combina- 
tions, while  the  intramolecular  possibilities  of  the  other 
elements  are  legion. 

When  to  this  very  complex  base  material  other  elements 
such  as  nickel,  chromium,  tungsten,  and  vanadium  are 
added,  we  begin  to  look  wise  and  talk  about  alloy  steels. 
Steels  within  the  limits  of  analysis  just  mentioned  serve 
an  enormous  number  of  purposes,  and  steel  of  a  particular 
analysis  adapted  for  rails,  springs,  knives,  or  gun  barrels 
may  in  a  limited  sense  be  called  a  "special"  steel,  but  such 
is  not  the  commonly  accepted  use  of  the  term. 

When  we  materially  exceed  the  limits  just  given  or  add 
elements  not  normally  contained,  such  as  nickel,  vanadium, 
chromium,  tungsten,  molybdenum,  etc.,  the  product  is 
called  an  alloy  or  special  steel.  Silico-manganese  gear 
steel  is  an  instance  of  an  alloy  steel  containing  no  unusual 
elements  but  containing  some  of  the  ordinary  elements  in 
unusual  amounts.  Its  analysis  is  about  as  follows :  Carbon, 
0.50  per  cent. ;  silicon,  2.00  per  cent. ;  manganese,  0.60 
per  cent. 

In  such  a  case  it  becomes  difficult  to  decide  arbitrarily 
the  percentage  at  which  we  pass  from  a  regular  to  a  special 
steel.  Abnormally  increasing  the  ordinary  constituents 
or  adding  other  constituents  so  changes  the  properties  that 
new  qualities  appear  and  new  purposes  are  served.  The 
effects  of  such  additions  are  made  manifest  in  various  ways 


TREATMENT  OP  ALLOY  STEEL      67 

which  may  be  summarized  as  follows:  1.  By  changing  the 
critical  ranges  and  recalescent  temperatures.  2.  By  modi- 
fying the  condition  in  which  the  carbon  exists.  3.  By 
removing  harmful  occluded  gaseous  impurities.  4.  By 
combining  chemically  with  iron  or  carbon  or  both.  5. 
Either  combined  or  free,  forming  isomorphous  solutions 
with  iron  or  separating  into  distinct  microscopic  particles. 
By  these  means  steel  is  improved  or  injured,  hardened  or 
strengthened,  toughened,  or  made  more  brittle. 

Notwithstanding  its  complexity,  it  is  reasonable  to  expect, 
and  much  evidence  has  been  brought  forward  to  show  that 
steel  and  its  alloys  obey  the  laws  of  physical  chemistry 
which  hold  good  for  simpler  and  purer  alloys,  namely,  the 
laws  of  solution.  The  problems  presented  by  steel  alloys 
have  engaged  the  attention  of  the  world's  leading  chemists 
and  physicists,  and  they  have  made  rapid  strides  within  a 
generation  in  elucidating  the  molecular  relations  of  the  ele- 
ments of  steel.  They  have  isolated  by  ingenious  methods 
many  well  defined  chemical  compounds,  such  as  the  car- 
bides, phosphides,  and  sulphides  of  iron  and  manganese. 

The  complexity  of  steel  from  a  chemical  standpoint  is 
further  increased  by  the  allotropic  character  of  iron,  and 
by  the  fact  that  carbon  and  probably  sulphur  and  phos- 
phorus may  exist  in  several  conditions  or  combinations. 
As  iron  is  cooled  from  a  molten  condition,  it  has  been  dis- 
covered that  at  from  one  to  three  temperatures  below  its 
freezing  point  cooling  momentarily  stops.  For  carbonless 
iron  these  temperatures  are  designated  as  Ar3  and  Ar2  and 
occur  at  about  895°  C.  and  765°  C.  When  carbon  is  also 
present  a  third  well  marked  arrest  in  cooling  is  noted  at 
about  690°  C.,  known  as  Arx— the  ordinary  ''recalescent'' 
point.  It  is  believed  by  many  that  the  Ar3  and  Ar2  tem- 
peratures indicate  transition  or  critical  changes  in  the 
nature  of  iron  itself.  In  other  words,  that  just  as  phos- 
phorus may  exist  in  two  distinct  forms,  one  yellow  and  one 
red,  so  the  element  iron  is  supposed  to  be  capable  of  exist- 
ing in  different  physical  conditions  at  different  temr>era^ 


68  MODERN  SCIENCE  READER 

tures.  At  temperatures  above  Ar3  we  have  the  "  gamma " 
iron  of  Osmond,  non-magnetic  and  a  solvent  for  both  ele- 
mental carbon  and  iron  carbide.  Between  the  Ar3  and  Ar2 
temperatures  we  have  iron  existing  in  its  "beta"  condi- 
tion, non-magnetic  but  not  a  solvent  for  free  or  combined 
carbon.  Below  Ar3  iron  is  in  its  "alpha"  condition,  mag- 
netic but  not  a  solvent  for  free  carbon,  but  possibly  a  slight 
solvent  for  combined  carbon.  While  some  metallurgists 
do  not  accept  this  explanation  of  the  significance  of  the 
critical  temperatures  and  ranges,  all  concede  that  they  do 
occur,  and  that  other  elements  added  to  iron  carbon  alloys 
change,  obliterate,  or  modify  the  temperature  ranges,  and  it 
is  just  on  account  of  this  that  different  steels  require  differ- 
ent temperatures  for  forging,  annealing  and  hardening. 

So  much  for  the  nature  of  alloy  steels,  and  now  a  few 
suggestions  as  to  their  treatment  and  a  few  words  as  to  the 
various  kinds  of  alloys.  The  constitution  of  these  products, 
chemical  and  physical,  for  generations  remained  unknown 
and  a  matter  of  speculation.  Tremendous  progress  has 
been  made  of  late  years  in  clearing  up  a  few  of  the  obscure 
points. 

The  first  commercial  alloy  steel,  at  least  the  first  to  make 
a  great  name  for  itself,  was  Mushet's  air  hardening  tool 
steel.  The  next  alloys  to  attract  attention  were  of  the 
structural  types,  and  may  be  said  to  have  had  a  public 
introduction  when  Riley  presented  a  paper  to  the  Iron  and 
Steel  Institute  of  Great  Britain  upon  iron  and  nickel. 
Shortly  afterward  Hadfield's  famous  manganese  steel  was 
proclaimed  and  later  he  has  produced  many  valuable  prod- 
ucts, especially  in  the  line  of  armor  and  projectile  steels. 
Along  with  the  making  of  the  new  products  has  proceeded 
the  study  of  their  properties  and  methods  of  heat  treat- 
ment. To-day  a  host  of  devotees,  skilled  in  the  science  of 
heat  treatment,  apply  their  knowledge  to  the  manufacture 
of  tools,  automobile  parts,  and  machinery  to  produce  re- 
sults never  dreamed  of  a  generation  ago. 

The  principal  types  of  alloy  steels  are  those  used  (1)  for 


TREATMENT  OP  ALLOY  STEEL      69 

materials  of  war,  (2)  for  tools,  and  (3)  for  materials  of 
construction.  The  first  are  mainly  alloys  of  nickel,  chro- 
mium, and  tungsten  or  combinations  of  these  elements. 
The  makers  of  these  alloys  also  conduct  the  heat  treatments 
and  guard  their  methods  jealously.  Alloy  tool  steels  in- 
clude air  hardening  and  high  speed  steels  together  with  a 
large  number  of  steels  of  the  "special"  class  containing 
relatively  small  amounts  of  alloying  elements,  giving  them 
special  characteristics  and  fitness  for  particular  and  severe 
requirements.  One  product  of  this  class  is  remarkable  in 
that  it  undergoes  no  change  in  form  upon  hardening ;  more- 
over, it  hardens  in  oil  sufficiently  to  make  a  remarkably 
good  tap,  cutter,  or  die. 

The  alloys  receiving  most  attention  to-day  are  those  of 
the  third  class— namely,  materials  of  construction,  and 
particularly  the  automobile  steels.  These  are  in  general 
of  three  kinds— nickel  steels,  chrome  nickel  steels,  and 
chrome  vanadium  steels.  Many  different  analyses  are  made 
under  each  class.  The  difficulty  of  producing  sound  nickel 
steel,  free  from  pipes  and  seams,  has  injured  the  reputa- 
tion of  this  most  useful  alloy  with  many  users.  This  dif- 
ficulty has  been  greater  than  need  be  because  certain  steel 
companies  have  mistaken  a  quality  proposition  for  a  ton- 
nage proposition,  and  have  offered  nickel  steel  at  absurdly 
low  prices,  wholly  inconsistent  with  uniformity  of  analysis, 
careful  workmanship  and  inspection.  Discriminating 
users  recognize  this  fact  and  are  willing  to  pay  a  premium 
for  the  product  of  certain  mills,  because  their  steels  are 
made  in  smaller  tonnages  and  units,  are  more  carefully 
handled  from  start  to  finish,  are  worked  under  hammers 
rather  than  in  blooming  mills,  are  made  from  purer  ma- 
terials and  carefully  inspected  when  done.  The  best  is 
none  too  good  for  constructing  the  vital  parts  of  an  automo- 
bile, and  when  a  concern  has  secured  the  best  that  the 
market  affords,  it  has  but  taken  the  first  step  in  producing 
good  parts.  Next  come  the  forging  and  machining  and 
the  heat  treatment,  for  better  or  worse.  It  is  money  wasted 


70  MODERN  SCIENCE  READER 

to  buy  good  alloys  unless  one  is  willing  to  study  them 
sufficiently  to  know  how  to  treat  them  and  then  to  supply 
adequate  facilities  for  so  doing. 

It  is  not  to  be  expected  that  small  users  will  install  com- 
plete testing  laboratories,  but  a  few  dollars  invested  in 
having  occasional  tests  made  will  be  well  spent.  There 
are,  however,  many  large  concerns  that  could  and  should 
spend,  say,  $5,000,  for  which  it  is  believed  the  whole  or  a 
large  part  of  the  following  equipment  could  be  obtained: 
The  ordinary  tensile  machine,  a  microscope,  electrical  or 
gas  furnaces  capable  of  fine  regulation,  a  good  pyrometer, 
preferably  recording.  The  tensile  machine  can  also  be  used 
for  making  Binnell  hardness  tests,  spring  deflection  tests, 
etc.  In  addition  to  these  some  form  of  drop  testing  ma- 
chine, such  as  the  Fremont,  will  be  found  valuable ;  a  vibra- 
tory or  repetitive  impact  test  is  nowadays  considered  a 
necessity,  while  cold  bending  and  torsion  apparatus  is  use- 
ful. This  equipment  will  be  of  small  use,  unless  a  thor- 
oughly good  man  is  put  in  charge— a  careful,  conscien- 
tious man  of  sound  judgment.  This  man  should  direct 
the  heating  operations  in  the  factory ;  he  should  construct 
furnaces  which  heat  uniformly,  and  he  should  exercise 
eternal  vigilance  in  keeping  the  pyrometric  installations 
up  to  par. 

The  best  pyrometer  of  the  thermo-couple  type1  should 
be  looked  over  and  calibrated  at  stated  intervals,  espe- 
cially if  in  constant  use.  Protecting  tubes  should  be  fre- 
quently examined  and  renewed,  and  electrical  contacts 
looked  over.  Occasionally  check  up  the  millivoltmeter. 
Unfortunately  there  are  many  pyrometers  of  the  thermo- 
couple type  on  the  market  which  cannot  be  watched  too 
closely.  Quite  recently  I  visited  two  concerns  where  they 
were  hardening  the  same  grade  of  steel  and  doing  it  well. 
I  a~:kod  each  concern  what  temperature  it  was  using.  One 
said  1,300°  F.  and  the  other  1,700°  F.  The  actual  tem- 
perature in  both  cases  was  probably  1,500°  F.  Another 
1  Compare  Fig.  2  in  ' '  Why  a  Flame  Emits  Light. ' ' 


TREATMENT  OF  ALLOY  STEEL      71 

so-called  cheap  pyrometer  that  I  tested  departed  from  the 
truth  over  100°  in  a  month,  and  another  was  50°  off  when 
installed.  In  a  lot  of  six  couples  tested  after  being  in  use 
some  time,  three  were  all  right  and  three  all  wrong  and  by 
varying  amounts.  If  you  are  going  to  use  pyrometers  by 
all  means  see  that  you  have  good  ones  and  then  see  that  they 
are  systematically  tested.  Many  people  buy  high  priced 
alloy  steels  and  get  no  better  results  from  them  than  could 
be  had  from  a  carbon  steel  properly  handled.  If  you  can- 
not afford  a  good  pyrometer  stick  to  the  trained  eye  of  a 
skilled  man;  and  if  you  have  a  good  pyrometer  employ  a 
skilled  man,  anyway,  and  consider  the  pyrometer  as  an  aid. 
With  it  you  can  at  least  give  orders  in  temperatures  rather 
than  in  heat  colors,  and  the  laboratory  and  works  can  meet 
on  an  intelligent  basis.  Pyrometers,  like  "smoke  consum- 
ers/' are  all  right  if  carefully  watched  and  intelligently 
used.  Too  often  both  fail  after  about  thirty  days'  use. 

Heat  treatment  operations  depend  upon  a  solid  scientific 
basis.  And  by  this  is  not  meant  that  steel  essentially  of 
inferior  quality  can  be  made  to  pass  muster  by  heat  treat- 
ment. 

On  the  other  hand,  however,  it  might  be  said  that  alloy 
steel  in  its  so-called  natural  state,  as  it  comes  from  the  rolls, 
hammer  or  drop  forge,  is  almost  unfit  for  automobile  con- 
struction. Steel  which  depends  upon  alloys  for  a  high 
elastic  limit  in  its  natural  condition  will  have  much  less 
elongation  than  the  same  steel  oil  tempered  and  annealed. 
For  example,  a  chrome  steel  gave  in  its  rolled  condition 
158,000  pounds  elastic  limit  and  5  per  cent,  elongation,  with 
9.4  per  cent,  reduction  of  area.  The  same  steel  oil  tempered 
and  annealed  gave  153,000  pounds  elastic  limit,  14  per  cent, 
elongation  and  52  per  cent,  reduction  of  area.  In  other 
words,  the  material  was  transformed  from  brittle  to  tough, 
from  treacherous  to  safe,  without  materially  affecting  its 
elastic  limit.  A  nickel  steel  similarly  treated  had  its  elas- 
tic limit  raised  20  per  cent.,  with  the  reduction  in  area 
improved  and  its  elongation  unchanged. 


OXYHYDRIC  PROCESS  OF  CUTTING 

METALS1 

TORCHES  AND   MACHINES   THAT    CUT   STEEL 
BY  E.  F.  LAKE 

IT  is  seldom  that  the  American  Machinist  has  the  privi- 
lege of  publishing  such  a  striking  addition  to  machine-shop 
methods  as  the  one  which  supplies  the  subject  of  this 
article.  When  we  say  that  Fig.  1  represents  a  piece  of 
9-inch  chrome-nickel  steel  armor  plate  which  has  been  cut 
to  a  circular  outline  by  the  removal  of  the  waste  piece 
shown  in  the  left  foreground,  and  that  this  has  been  done 
at  the  rate  of  a  linear  foot  of  cut  in  21/4  minutes,  we  think 
we  are  saying  enough  to  indicate  that  here  is  something 
new  in  the  machine  shop. 

Fig.  2  shows  the  work  in  progress  with  the  pyrotechnic 
display  that  accompanies  it.  Further  on  in  this  article 
additional  examples  of  the  work  done  will  be  shown  which 
are  less  striking  than  the  one  which  forms  the  subject  of 
the  first  two  pictures  only  because  of  the  smaller  sizes  of 
material  acted  upon.  In  some  respects— notably  the  form 
of  the  cut  made  in  some  of  the  examples— these  latter  cases 
are,  indeed,  more  striking  than  the  ones  shown  in  Figs.  1 
and  2. 

The  remarkable  results  are  obtained  by  an  apparatus 
which  is  a  development  from  one  patented  in  1901  by  the 
Cologne-Meusen  Mining  Company  for  opening  plugged 
blast  furnace  tap  holes  and  now  in  considerable  use  in  this 
country,  where  it  has  cut  tap  holes  through  4  feet  or  more 
of  solid  metal,  and  with  a  reduction  of  time  from  days  to 
as  many  hours.  That  apparatus,  like  this,  makes  use  of 

1  Abstract  of  an  article  published  in  the  American  Machinist, 
1909. 

72 


THE  OXYHYDRIC  PROCESS  73 

two  nozzles  through  one  of  which  a  mixture  of  oxygen  and 
hydrogen  is  supplied,  while  the  other  delivers  pure  oxygen 
only.1  The  action  of  the  older  apparatus  is,  however,  to 
actually  melt  the  metal,  and  while  very  effective  for  its 
purpose,  it  is  impossible  by  it  to  produce  a  smooth  and 
exact  cut  of  any  desired  length. 

With  the  present  apparatus  a  preheating  nozzle,  deliver- 
ing mixed  oxygen  and  hydrogen,  is  used  to  continuously 
heat  the  metal,  while  immediately  following  it,  and  set  at 
an  angle  such  that  both  streams  of  gas  strike  the  metal  at 
the  same  place,  is  a  second  nozzle  delivering  pure  oxygen 
only.  This  cuts  the  metal  by  oxidizing  it  without  melting 
and  blows  away  the  oxides  by  the  force  of  the  blast.  The 
result  is  a  cut  which  may  be  fairly  compared  with  that 
made  by  a  cutting  tool,  while  the  heating  is  so  local  that 
the  properties  of  the  material  cut  are  not  affected  beyond 
about  %4-inch  of  the  cut  surface  and  the  width  of  the 
kerf  is  surprisingly  small. 

The  oxyhydric  process  is  based  on  the  well-known  fact 
that  iron  burns  easily  and  rapidly  in  an  atmosphere  of  oxy- 
gen gas,  as  much  heat  is  thus  set  free.  If  we  throw  a  jet  of 
oxygen  upon  iron  that  has  been  heated  to  red,  the  oxygen 
oxidizes  the  metal,  which  is  to  say,  burns  it.  Thus  the  steel 
is  heated  only  to  from  1,300°  to  1,500°  F.,  as  at  this  temp- 
erature iron  has  a  great  affinity  for  oxygen,  and  the  com- 
bination produces  different  forms  of  oxides. 

The  double-nozzle  torch  may  be  manipulated  by  hand, 
or  it  may  be  guided  by  any  sort  of  mechanical  arrangement ; 
and  thin  sheets  or  thick  plates,  steel  tubes,  structural 
shapes,  castings,  or  any  odd  pieces  of  steel  may  be  easily 
cut. 

The  cut  can  be  made  to  follow  any  sort  of  a  line  what- 
ever, as  all  forms  of  curves  and  odd  shapes  are  cut  as 
easily  as  the  straight  line.  The  cut  is  not  necessarily 
square  to  the  surface,  as  a  beveling  cut  can  be  easily  made, 

'Acetylene  is  being  used  in  this  country  in  place  of  hydrogen,  with 
some  makes  of  torches. 


74  MODERN  SCIENCE  READER 

and  it  is  practically  no  wider  at  the  bottom  than  at  the  top 
even  when  cutting  very  thick  metal.  The  speed  of  travel 
of  the  torch  can  be  made  about  8  inches  per  minute  on 
fairly  thick  metal,  and  this  makes  it  compare  very  favor- 
ably with  hot  sawing. 

The  composition  of  the  steel  or  its  mechanical  treatment 
does  not  affect  the  speed  with  which  the  metal  is  cut,  or 
the  amount  of  gas  which  is  used  in  the  cutting.  In  fact, 
there  is  no  variation  between  the  rolled,  forged,  or  cast 
steels  and  the  soft,  hardened,  tempered,  carbonized  or 
Harveyized  steel ;  and  a  nickel  chrome,  high  manganese  or 
high  carbon  steel  cuts  as  easily  as  the  low  carbon  steels. 

The  complete  apparatus  for  cutting,  with  one  of  the 
mechanical  appliances  for  guiding  the  torch,  is  shown  in 
Fig.  3.  The  two  steel  bottles  at  the  right  of  the  picture 
contain  the  oxygen  and  hydrogen  which  is  stored  under  a 
pressure  of  from  1,500  to  2,000  pounds  per  square  inch. 

Each  bottle  is  provided  with  a  needle  valve  to  which  is 
attached  a  pressure  regulator  governing  the  flow,  so  that 
the  gas  will  be  delivered  to  the  mixer  and  from  thence  to 
the  torch  at  a  constant  pressure.  A  high-pressure  gage  is 
located  between  the  needle  valve  and  pressure  regulator  in 
order  to  show  at  all  times  the  contents  of  the  tank  and  to 
determine  the  amount  of  gas  consumed  in  any  cutting 
operation.  A  low-pressure  gage  is  also  attached  to  the 
regulator  showing  the  pressure  of  gas  as  used'  for  cutting. 
The  cutting  pressure  can  thus  be  varied  to  suit  the  char- 
acter of  the  work  by  turning  a  thumb  screw  on  the  regu- 
lator. From  the  regulator  the  gas  is  conducted  by  heavily 
armored  tubing  to  the  mixer. 

The  mixer  is  shown  on  the  floor  beside  the  bottles  and 
the  gases  are  conducted  through  it  by  a  conical  worm- 
shaped  pipe  made  of  thin  metal,  this  pipe  being  surrounded 
by  cool  water  as  a  safety  provision  against  explosion  of  the 
mixed  gases. 

In  Fig.  3  the  torch  rides  on  a  frame  that  is  provided 
with  two  ways  for  guiding  it  in  a  straight  line. 


THE  OXYHYDRIC  PROCESS  75 

On  steel  four  inches  thick,  the  width  of  the  cut  is  only 
one  eighth  of  an  inch,  while  on  thin  metal  it  is  but  five 
sixty-fourths  inch,  and  the  metal  is  practically  as  smooth 
as  that  coming  from  a  saw. 

The  principal  item  in  the  cost  of  cutting  metal  with  this 
process  is  the  gases  used,  as  the  apparatus  is  much  simpler 
than  that  used  for  cutting  metals  by  any  other  means,  and 
requires  no  power,  and  the  time  of  cutting  is  as  quick  if 
not  quicker.  The  consumption  of  gas  naturally  depends 
upon  the  thickness  of  the  piece  to  be  cut. 

From  the  large  amount  of  work  which  has  been  done 
and  the  numerous  thicknesses  of  metal  which  have  been 
cut,  the  amount  of  gases  which  should  be  used  are 
pretty  well  known.  In  table  II1  is  given  the  amount  of 
the  two  gases  which  should  be  used  for  all  thicknesses 
of  metal  from  one  tenth  of  an  inch  to  five  inches,  as 
well  as  the  size  of  nozzle  which  should  be  used  for  each 
gas. 

In  a  machine  which  is  designed  for  accurate  straight 
cuts  either  parallel  with  or  at  right  angles  to  the  bed  of 
the  frame,  the  torch  is  mounted  on  a  carriage  which  is 
moved  longitudinally  by  hand  wheels  and  a  lead  screw. 
Another  hand  wheel  on  the  side  of  the  carriage  moves  the 
torch  away  from  or  toward  the  machine,  and  as  the  oxygen 
nozzle  should  always  follow  the  preheating  nozzle,  the 
torch  may  be  turned  around  by  a  small  lever.  This  torch, 
as  are  all  the  torches,  is  provided  with  a  valve  for  shutting 
off  the  gas.  At  the  bottom  of  the  machine  is  located  a 
straight  edge  on  which  the  nozzle  slides.  By  means  of  an 
additional  attachment  the  torch  can  be  made  to  cut  in  a 
vertical  direction. 

In  Fig.  4  are  shown  some  samples  of  the  work  done  with 
the  above  machine.  The  slabs  themselves  were  first  cut 
off  with  the  oxyhydric  torch,  and  afterward  the  irregular 
cuts  were  made  in  the  slabs.  The  narrowness  of  the  cut, 
the  square  corners  that  it  is  possible  to  turn,  and  the  fact 
1  See  original  article  for  these  figures, 


76  MODERN  SCIENCE  READER 

that  the  metal  is  not  burned  on  the  sides  of  the  cut  are 
plainly  seen. 

The  closeness  with  which  the  metal  can  be  cut  to  a  line 
is  best  illustrated  by  the  small  slab  in  the  upper  right 
hand  corner.  In  the  center  of  the  slab  it  will  be  noticed 
that  there  has  been  left  a  thin  strip  of  metal.  This  is  but 
one  eighth  of  an  inch  thick,  while  the  cut  is  one  and  one- 
fourth  inches  deep,  and  is  practically  no  wider  at  the 
bottom  than  at  the  top. 

Another  appliance  can  be  used  in  an  ordinary  brace  for 
cutting  circles  from  two  to  twelve  inches  in  diameter,  and 
yet  another  can  be  attached  to  a  beam  located  in  a  trammel 
point  for  cutting  larger  circles.  The  torch  is  fastened  by 
thumb  screws  to  two  U-shaped  rods  that  are  mounted  on 
wheels.  Either  of  these  rods,  or  both  together,  can  be 
raised  or  lowered  so  as  to  accommodate  the  torch  to  any 
inequalities  in  the  surface  of  the  metal,  or  to  locate  it  the 
proper  height  above  the  metal  for  successful  cutting. 

One  of  the  most  useful  applications  of  this  process  is  in 
the  cutting  of  steel  tubes  or  pipe.  A  special  attachment 
has  been  made  for  this  purpose.  It  is  made  in  several 
sizes  to  accommodate  the  different  sizes  of  pipe. 

The  pipe  is  inserted  in  the  center  of  a  ring  and  is 
clamped  there  by  three  set  screws.  The  torch  is  then 
revolved  around  the  pipe  and  cuts  it  with  a  good  clean  cut 
and  hardly  any  waste  of  metal.  A  small  wheel,  that  runs 
around  the  pipe  back  of  the  nozzles,  locates  their  position, 
and  adjustment  can  be  obtained  by  means  of  a  spring  in- 
side of  the  apparatus.  This  apparatus  is  especially  valu- 
able in  plants  where  power  is  not  available. 

Another  style  of  pipe  cutting  machine  is  built,  which 
can  be  used  on  pipe  that  has  flanges  on  both  ends,  and  it 
is  made  so  it  can  be  adjusted  to  fit  different  diameters  of 
pipe.  This  machine  can  be  used  for  cutting  the  openings 
for  branch  connections  Branch  flanges  can  also  be  cut  out. 

A  manhole  cutting  machine  is  also  made  which  will  cut 
oval,  round,  and  square  holes  up  to  eight  inches  square. 


THE  OXYHYDRIC  PROCESS  77 

One  of  the  most  interesting  jobs  which  has  been  done 
with  this  process  was  the  taking  apart  and  cutting  into 
scrap  of  an  old  English  armored  cruiser,  which  had  been 
bought  by  a  firm  in  Hamburg. 

The  method  which  had  been  employed  formerly  was  to 
cut  the  rivets  off,  drive  them  out,  remove  the  armor  plate, 
notch  it  with  compressed  air  tools  and  then  break  it  up 
under  a  drop.  To  complete  the  work  by  this  old  method 
usually  took  one  and  one-half  years.  Now,  with  the 
oxyhydric  process,  the  job  was  completed  in  two  and  one- 
half  months. 

The  armor  plate,  as  it  was  being  cut  up,  is  shown  in 
Fig.  5.  Some  of  this  was  fourteen  inches  thick  and  some 
of  the  heaviest  guns  which  were  cut  up  had  an  outside 
diameter  of  more  than  forty  inches.  All  the  metal  in  the 
boat  was  cut  to  sizes  suitable  for  charging  in  the  furnaces 
for  remelting.  See  Fig.  6. 

As  a  manufacturing  proposition  the  oxyhydric  process  is- 
equally  as  good  as  in  the  cutting  up  of  scrap,  and  Fig.  7 
shows  a  sample  of  work  on  which  it  is  very  useful.  This 
is  a  face  plate  for  the  base  frame  of  a  locomotive.  It  was 
nine  sixteenths  of  an  inch  thick,  four  feet  wide  by  six  feet 
long  and  about  264  lineal  inches  had  to  be  cut  in  cutting 
out  the  opening.  This  work  was  done  in  exactly  one  hour, 
which  is  at  a  speed  of  three  and  three-fourths  minutes  for 
each  running  foot. 

Many  uses  for  this  process  will  also  be  found  in  steel 
foundries.  In  Fig.  8  is  shown  a  steel  casting  just  as  it 
comes  from  the  mold,  and  Fig.  9  shows  the  same  casting 
after  the  sprues,  risers,  etc.,  have  been  cut  off  with  the 
oxyhydric  process. 

The  oxyhydric  process  is  also  applicable  for  welding  the 
various  metals  that  can  be  fused  together.  The  flame,  how- 
ever, must  be  the  opposite  of  that  used  for  cutting  metals, 
as  it  must  be  one  that  freely  reduces  the  oxide,  rather  than 
one  causing  oxidation,  as  is  used  in  cutting,  as  oxides  in 
the  welds  are  inadvisable. 


78  MODERN  SCIENCE  READER 

In  the  apparatus  that  is  used  for  welding  the  same 
two  oxygen  and  hydrogen  bottles  are  used  and  the  gas  is 
piped  from  these  to  the  same  mixer  that  is  used  in  cutting. 
Here,  however,  the  similarity  ceases  as  the  extra  nozzle  for 
oxygen  is  not  used.  A  torch  with  a  single  nozzle  is  sub- 
stituted and  the  gas  that  enters  the  torch  is  piped  through 
a  single  pipe  from  the  mixer ;  thus  only  one  line  of  armored 
hose,  leading  to  the  torch,  is  needed  in  place  of  the  two. 

The  welding  done  by  this  method  leaves  the  metal  its 
ductility.  If  the  welded  joint  is  submitted  to  a  slight 
hammering,  while  it  is  cooling  down  to  a  dull  red,  or  even 
to  a  heat  treatment  after  it  has  cooled,  the  steel  in  most 
cases  can  be  brought  back  to  its  original  structure  and  the 
joints  can  be  made  nearly  as  strong  as  the  original  metal. 

In  welding  thick  plates,  say  from  three  eighths  of  an 
inch  upward,  by  any  of  the  fusion  methods,  it  is  usual  to 
bevel  or  chamfer  the  two  edges  of  the  joints  and  fill  the  V 
thus  formed  by  melting  metal  from  a  rod,  with  the  torch. 
If  the  metal  is  properly  fused  by  this  method  a  fairly  good 
joint  is  obtained,  but  if  the  operator  allows  globules  of 
metal  to  fall  from  the  rod  and  drop  on  metal  which  has 
not  been  properly  melted,  the  two  do  not  fuse  together  and 
a  poor  joint  is  the  result. 

The  German  Oxyhydric  Company  adopted  a  different 
method  of  welding  metals  from  three  eighths  to  one  inch 
thick,  and  have  made  many  successful  welds  thereby.  This 
method  is  to  put  the  two  ends  of  the  metal  together  with- 
out overlapping,  but  in  contact  with  each  other.  They  are 
thus  heated  by  two  oxyhydric  torches,  one  above  and  the 
other  below  the  metal,  and  exactly  opposite  each  other,  and 
are  given  as  extensive  a  heating  zone  as  possible. 

When  the  metal  begins  to  show  signs  of  melting  on  the 
outside,  the  interior  of  the  sheets  are  doubtless  at  a  white 
welding  heat;  the  torches  are  then  removed  and  an  anvil 
and  hammer  brought  into  use  for  lightly  hammering  the 
joint.  This  causes  a  readjustment  of  the  molecules,  and 
they  join  together  in  the  weld. 


FIG.  4. — IRREGULAR  SHAPED  CUTS 


FIG.   5. — CUTTING   UP   THE   ARMOR  PLATE,   SOME  OF   WHICH  WAS 
14  INCHES  THICK 


FIG.  6. — CUTTING  CAST-STEEL  FRAME  FOR  PROPELLER  SHAFT 


FIG.  7. — HOLES  CUT  IN  PLATE  4x6 
FEET,  T9«j  INCH  THICK.  CUT,  264 
INCH.  TIME,  1  HOUR 


FIG.  8. — STEEL  CASTING  AS  IT  LEFT  THE 
MOLD 


FIG.  9. — SAME  CASTING  AFTER  CUTTING 
RISERS,   SPRUES,  ETC. 


FIG.  10. — WELDING  LEAVES  AND  PETALS  ox  BLACKSMITH'S 
ART  WORK 


FIG.  11. — DAVIS-BOURNONVILLE  PROCESS 

A  rush  job.  Corliss  engine  cylinder,  weight,  3,800  Ibs. ;  length,  5  ft. ; 
height,  3  ft.  2  in.,  bore,  20  in.  Breaks  Avelded  in  one  day.  It 
would  have  taken  three  months  to  have  obtained  a  new  cylinder, 
and  the  expense  of  tying  up  the  plant  that  long  would  have  been 
great.  Had  been  in  use  two  months  when  the  report  was  made 
on  the  job.  (Davis-Bournonville  Co.'s  oxyacetylene  process  of 
cutting  and  welding.) 


THE  OXYHYDRIC  PROCESS  79 

In  welding,  one  part  of  oxygen  to  from  four  to  six  parts 
of  hydrogen  are  used,  and  it  is  necessary  to  obtain  a  com- 
plete absorption  of  the  oxygen,  by  the  hydrogen  in  excess, 
in  order  to  make  a  perfectly  homogeneous  flame.  This  was 
a  difficult  problem  to  solve  as  the  fear  of  explosion  long 
prevented  the  mixing  of  the  two  gases  before  their  in- 
flammation. 

It  was  overcome  by  assuring  to  the  mixture  of  the  gases 
a  velocity  greater  than  the  velocity  of  the  propagation  of 
the  flame,  as  an  explosive  mixture  contained  in  a  tube  does 
not  ignite  instantaneously  in  all  of  its  mass  when  combus- 
tion is  started  at  one  end  of  the  tube. 

The  ignition  is  propagated  in  the  tube  with  a  finite 
velocity  which  increases  as  the  square  of  the  section 
thereof.  If,  therefore,  the  gaseous  mass  moves  toward 
the  point  of  ignition  with  a  speed  greater  than  the  speed 
of  propagation,  the  flame  will  not  reach  the  inside  of  the 
torch  and  much  less  that  of  the  mixer. 

Thus,  having  obtained  a  minimum  for  the  speed  to  be 
given  the  gas,  it  is  necessary  not  to  exceed  the  maximum, 
and  this  is  obtained  by  a  practical  consideration,  namely, 
that  the  jet  of  gas  leaving  the  torch  must  not  be  strong 
enough  to  set  in  motion  the  drops  of  the  metal  which  are 
intended  to  constitute  the  weld. 

In  operation  the  two  gases  are  carried  from  the  steel 
bottles  to  the  mixer  where  they  are  mixed  as  previously 
described  from  the  cutting  operation.  From  the  mixer 
they  are  carried  to  the  torch  through  a  single  tube  and 
enter  this  where  there  is  a  sharp  enlargement  in  its  shape. 
This  considerably  diminishes  the  velocity  of  the  gases,  and 
from  there  they  pass  through  a  conical  tube  that  is  per- 
fectly smooth  on  the  inside.  This  tube  gradually  dimin- 
ishes in  size  down  to  the  nozzle,  and  the  speed  of  the  gases 
gradually  increases  again  until  the  minimum  speed  required 
is  obtained. 

As  a  sample  of  some  of  the  fine  work  which  can  be  done 
by  welding  with  the  oxyhydric  process,  Fig.  10  shows  an  arl 


80  MODERN  SCIENCE  READER 

piece  in  which  the  leaves,  petals,  stems,  and  ribbon  are 
worked  out  by  a  blacksmith  with  a  hammer  and  anvil,  and 
the  whole  was  then  welded  together  by  welding  the  leaves 
and  petals  to  the  stem.  Fig.  11  shows  some  difficult  weld- 
ing done  in  this  country  by  the  Davis-Bournonville  oxy- 
acetylene  process, 


THE  COMMERCIAL  PRODUCTION  OF 
OXYGEN1 

BY  ALFEED  GRADENWITZ,  PH.  D. 

THE  European  oxygen  industry  is  passing  through  a 
period  of  most  remarkable  development.  Oxygen  factories 
are  springing  up  everywhere  to  produce  this  valuable  gas, 
which  especially  in  .metallurgy  is  now  utilized  for  many 
purposes.  This  fact  is  due  in  a  large  part  to  the  great  im- 
provements that  have  taken  place  during  the  last  few 
years  in  the  methods  of  liquefying  air  and  separating  it 
into  its  constituents,  oxygen  and  nitrogen.  The  process 
due  to  Professor  Linde,  the  celebrated  scientist  of  Munich, 
Bavaria — which  is  based  on  the  expansion  of  compressed 
air  and  the  production  of  internal  work  during  expansion 
through  a  constricted  orifice— is  fairly  well  known  in  this 
country.  In  order  to  obtain  oxygen,  Professor  Linde  lique- 
fies completely  some  atmospheric  air,  so  as  to  produce  a 
liquid  containing  twenty-one  per  cent,  of  oxygen,  which  is 
then  caused  to  flow  down  a  rectifying  column  similar  to 
those  used  in  distilling  alcohol  or  gasoline.  In  this  column 
the  liquid  meets  with  oxygen  vapors  resulting  from  the 
liquid  oxygen,  which  is  vaporized  by  the  latent  heat  of  the 
air  in  course  of  liquefaction ;  in  this  way  a  pure  commercial 
oxygen  (ninety-six  to  ninety-eight  per  cent.)  is  eventually 
obtained,  while  the  nitrogen  produced  at  the  same  time 
still  contains  at  least  seven  per  cent,  of  oxygen,  that  is, 
one  third  of  the  oxygen  of  air. 

Although  giving  better  results,  Claude's  process  is  not 
perhaps  so  well  known  outside  of  the  Continent  because  of 
its  more  recent  origin.  It  is  worked  in  France  by  L'Air 

Published  in  Scientific  American  Supplement,  April  10,   1909. 
6  81 


82  MODERN  SCIENCE  READER 

Liquide,  Ltd.,  at  Paris,  Lyons,  Marseilles,  and  in  Belgium 
at  Dugree  near  Liege,  while  in  October  new  works  will  be 
opened  in  Italy  and  Germany. 

In  the  Claude  process  for  the  liquefaction  of  air,  the 
expansion  of  compressed  air  with  the  production  of  recov- 
erable external  work  is  made  use  of,  that  is,  expansion  takes 
place  on  the  piston  of  a  reciprocating  engine.  Though  this 
method,  according  to  theory,  gives  far  better  yields  than 
that  of  expansion  through  a  valve,  many  scientists  previous 
to  Claude  (such  as  Siemens,  Solvay,  Hampson)  in  vain 
endeavored  to  carry  out  the  expansion  of  compressed  air 
in  an  engine,  and  Linde  even  believed  it  to  be  utterly 
impossible. 

There  was,  in  fact,  one  great  difficulty  to  be  overcome  in 
this  connection,  viz.,  the  lubrication  of  an  engine  at  such 
low  temperatures  that  all  lubricating  substances  would 
have  become  frozen.  Claude  succeeded  in  eliminating  this 
difficulty  by  using  light  petroleum  ethers,  which  at  ordinary 
temperatures  are  not  lubricants,  but  acquire  lubricating 
properties  as  the  temperature  is  getting  very  low.  Claude 's 
first  successful  experiments  were  officially  announced  to 
the  French  Academy  in  1902  by  the  well-known  physicist, 
Professor  d'Arsonval. 

In  Claude's  original  machine  (see  Fig.  1)  the  compressed 
air  was  cooled  in  the  inner  tube  of  the  exchanger  J/,  in 
order  then  to  be  expanded  in  the  engine,  the  liquefied 
portion  being  collected  at  the  end  of  the  expansion  in  the 
receptacle  R,,  while  the  unliquefied  portion  was  allowed  to 
flow  through  the  outer  tube  B  of  the  exchanger  M,  thus 
cooling  the  incoming  compressed  air. 

It  is  true  that  this  original  system  failed  to  give  really 
satisfactory  results,  because  of  the  many  difficulties  arising 
from  the  liquefaction  taking  place  in  the  cylinder  itself; 
as  moreover  liquefaction  is  effected  at  —190°  C;  (—310° 
F.)  at  the  end  of  expansion  and  under  atmospheric  pres- 
sure, the  air  in  this  condition,  after  traversing  the  ex- 
changer, reaches  the  engine  at  about  —135°  C.  (—211°  F.), 


PRODUCTION  OF  OXYGEN 


83 


84  MODERN  SCIENCE  READER 

at  which  temperature  it  no  longer  obeys  Boyle's  law,  but 
contracts  much  more  than  would  correspond  to  the  latter. 
A  considerable  excess  of  air  should  therefore  be  thrown 
into  the  engine,  in  order  actually  to  produce  an  amount  of 
cold  as  corresponding  to  theoretical  calculation. 

This  drawback  is  greatly  diminished  by  raising  the 
initial  temperature  of  expansion  from  —135°  C.  (—211° 
F.)  to  —100°  C.  (—148°  F.)  ;  and  in  order  to  achieve  this 
result,  Claude  interposes  between  the  temperature  ex- 
changer and  the  expansion  engine  an  apparatus  L,  called 
" liquef actor, "  (Fig  2),  into  which  part  of  the  compressed 
air  is  thrown  after  its  passage  through  the  exchanger. 

The  air  in  L  being  under  a  pressure  of  about  40  atmos- 
pheres will  not  liquefy  as  in  Fig.  1  at  —190°  C.  (—310° 
F.),  but  at  —140°  C.  (—220°  F.),  which  is  the  critical 
temperature  of  air.  The  air  expanded  in  the  engine  ac- 
cordingly is  first  heated  in  L  up  to  —140°  C.  (—220°  F.), 
before  entering  the  exchanger  M,  instead  of  being  at  a 
temperature  of  —190°  C.  (—310°  P.),  as  in  the  original 
apparatus.  The  air  admitted  into  the  engine  thus  is  at  a 
somewhat  higher  temperature.  This  liquefying  process, 
which  is  called  by  the  inventor  "liquefaction  under  pres- 
sure," can  yield  one  liter  of  liquid  air  for  each  horse- 
power hour. 

This  remarkable  process  seems  to  have  been  recently  imi- 
tated by  several  constructors,  such  as,  e.  g.,  an  engineer  of 
the  New  England  Refrigerating  Company,  of  Norwich, 
Mr.  Place,  who  in  describing  this  process,  states  that: 

"The  cold  exhaust  air  from  the  engine  is  carried  over 
pipes  containing  air  to  be  liquefied  (in  an  opposite  direc- 
tion thereto)  which  is  at  a  higher  pressure  of  600  pounds; 
this  exhaust  air  is  then  carried  back  over  the  incoming 
compressed  air  being  supplied  to  the  engine,  and  cools  that 
cold  air.  .  .  ."  In  fact,  this  process  is  identical  with  the 
one  indicated  by  Claude  in  1902. 

In  order  then  to  separate  the  oxygen  from  the  nitrogen, 
Claude  uses  a  method  based  on  the  partial  liquefaction  of 


PRODUCTION  OF  OXYGEN 


85 


86 


MODERN  SCIENCE  READER 


air.  Although  so  competent  an  authority  as  Sir  J.  Dewar 
emphatically  denied  the  possibility  of  partially  liquefy- 
ing air,  maintaining  that  the  oxygen  would  come  down 
together  with  the  whole  of  the  nitrogen,  Claude  succeeded 
in  experimentally  demonstrating  that  his  idea  could  very 
well  be  carried  out  in  practice,  a  liquid  rich  in  oxygen 
being  at  first  given  out  from  air.  In  Claude's  process,  this 
partial  liquefaction  is  combined  with  what  is  called  the 
"backward  return"  of  the  liquid  portions,  this  additional 
factor  being  necessary  to  allow  of  a  satisfactory  separation 
of  the  air  in  course  of  liquefaction. 

M 


FIG.  3. — SYSTEM  OF  COOLING  AND  LIQUEFYING  COMPRESSED  AIR 


In  Fig.  3  the  compressed  air  cooled  in  the  exchangers 
M  and  N,  after  entering  the  apparatus  in  T,  is  liquefied 
gradually  in  the  set  of  tubes  F  surrounded  by  liquid  air, 
the  first  drops  containing  about  48  per  cent,  of  oxygen. 

While  the  remaining  gas,  which  is  a  little  poorer  in 
oxygen  than  air,  rises  higher  up  in  the  tubes,  a  liquid  comes 
off  containing  less  than  48  per  cent,  of  oxygen.  However, 
as  soon  as  some  liquid  is  produced  in  the  tubes,  it,  owing 


PKODUCTION  OF  OXYGEN 


87 


to  its  weight,  returns  backward  in  an  opposite  direction  to 
the  ascending  gases  and  in  contact  with  them,  so  that  part 
of  the  oxygen  of  those  gases  is  liquefied,  replacing  a  cor- 
responding amount  of  liquid  nitrogen,  which  is  vaporized. 

The  same  process  is  repeated  throughout  the  length  of 
the  tubes,  and  allows  a  liquid  to  be  obtained  holding  forty- 
eight  per  cent,  of  oxygen  and  comprising  the  whole  of  the 
oxygen  of  the  air,  leaving  on  the  other  hand  pure  gaseous 
nitrogen. 

In  spite  of  these  remarkable 
results,  the  partial  liquefaction 
conducted  under  the  conditions 
described  still  proved  inade- 
quate for  manufacturing  pure 
oxygen.  The  latter  was  ob- 
tained only  by  combining  the 
principle  of  liquefaction  as 
above  described  with  the  rectify- 
ing process  used  for  many  years 
in  the  distilling  industries. 
1  Fig.  4  shows  the  apparatus 
constructed  for  this  purpose. 
The  cold  compressed  air  at  A 
enters  the  tubes  F,  and  is  par- 
tially liquefied  in  the  latter. 
The  liquid  thus  formed  returns 
in  an  opposite  direction  to  the 
ascending  gases,  and  finally 
yields  a  liquid  containing  about 
forty-eight  per  cent,  of  oxygen, 
while  pure  gaseous  nitrogen 
comes  out  at  the  top  of  the  tubes  Fl(J  4> J^RATUS  FOR  SEP- 
F,  in  order  then  to  be  liquefied  ABATING  ATMOSPHERIC  AIR 
in  the  tubes  F'.  The  liquid  rich 
in  oxygen  collected  at  C,  owing 
to  its  pressure,  is  poured  out  in  the  central  part  of  the 
column,  and  rectifies  the  ascending  gases  up  to  a  percentage 


-f 
-V 


INTO    PURE 
NITROGEN 


OXYGEN    AND 


88  MODERN  SCIENCE  READER 

of  twenty-one  per  cent.,  while  the  liquid  nitrogen  collected 
at  C"  is  poured  out  from  the  top  of  the  column,  and  submits 
the  gases  at  twenty-one  per  cent,  to  a  further  rectification. 

After  having  been  washed  by  pure  liquid  nitrogen,  the 
gas  finally  becomes  itself  pure  nitrogen  gas,  coming  out  of 
the  apparatus  at  E. 

The  pure  oxygen  resulting  from  rectification  at  the  bot- 
tom of  the  column  is  vaporized  at  "F,  the  greater  part  of  it 
entering  the  column  of  rectification,  while  the  remainder 
comes  out  at  T  and  is  then  collected. 

By  this  means  an  integral  separation  of  atmospheric  air 
into  its  constituents,  pure  oxygen  and  pure  nitrogen,  is 
carried  out. 

Figure  5  illustrates  a  plant  which  is  able  to  turn  out 
each  hour  as  much  as  50  cubic  meters  (1,776  cubic  feet) 
of  oxygen. 


FIG.  5. — APPARATUS  FOR  THE  PRODUCTION  OF  OXYGEN 


WHY  A  FLAME  EMITS  LIGHT— THE 
DEVELOPMENT  OF  THE  THEOKY1 

BY  KOBEET  MONTGOMEEY  BIKD,  PH.  D. 

As  one  would  naturally  suppose,  the  theory  now  generally 
held  regarding  the  nature  of  an  ordinary  name  and  its 
power  to  emit  light  is  not  altogether  the  result  of  modern 
research,  but  one  which  has  been  evolved  from  very  ancient 
and  hazy  notions.  Naught  else  is  to  be  expected  when  we 
consider  the  important  place  fire  has  held  throughout  the 
development  of  mankind.  It  is  the  first  recorded  object  of 
his  worship,  and  we  have  reason  to  believe  that  all  architec- 
ture had  its  beginning  in  rude  structures  erected  to  protect 
the  sacred  fire.  It  is  not  the  nature  of  man  to  see  phenom- 
ena so  striking  as  those  which  attend  the  consumption  of 
matter  by  fire  and  not  speculate  upon  them.  But  the  cen- 
turies had  multiplied  and  modern  times  had  been  reached 
before  man's  ideas  regarding  fire,  flame  and  light  became 
distinct,  and  the  use  of  these  terms  differentiated.  The 
best  text-books  and  works  on  natural  philosophy  published 
near  the  end  of  the  eighteenth  century  still  used  the  terms 
with  great  looseness,  and  the  conceptions  of  the  material 
nature  of  flame  and  light  were  yet  in  their  death  struggles. 

After  the  corpuscular  theory  of  light  had  given  place  to 
the  wave  theory,  conflicting  ideas  arose  as  to  why  and  how 
a  flame  emits  light  waves.  When  it  was  agreed  that  the 
waves  were  sent  out  by  solid  particles  of  carbon  heated  to 
incandescence,  the  question  of  the  origin  of  the  carbon,  or 
the  chemical  changes  taking  place  in  the  flame,  was  dis- 
cussed, and  along  with  this  the  source  of  heat  which  renders 
it  incandescent.  The  last  and  most  generally  accepted 

'Published  in  Popular  Science  Monthly,   1903. 
89 


90  MODERN  SCIENCE  READER 

answer  to  these  two  questions— the  origin  of  carbon  parti- 
cles and  the  source  of  heat— is  given  in  the  "acetylene 
theory,"  first  advanced  in  1892  by  Professor  Vivian  B. 
Lewes,  of  England. 

This  theory  expressed  briefly  is  that  a  portion  of  the 
hydrocarbon  gas,  by  the  heat  of  combustion  of  another  por- 
tion, is  converted  into  acetylene,  and  that  this  on  being 
decomposed  by  heat  furnishes  the  carbon  particles,  which 
particles  are  rendered  incandescent  mainly  by  the  heat 
liberated  when  the  gas  is  decomposed;  acetylene  being  a 
substance  which  absorbs  heat  during  its  formation  and 
hence  liberates  heat  when  it  breaks  down.  Whatever  is 
burned,  whether  a  solid  candle  or  liquid  oil,  must  pass 
through  the  gaseous  state,  and  hence  this  applies  to  all 
flames  used  for  lighting  purposes. 

But  before  explaining  this  theory  more  fully  and  seeing 
upon  what  experimental  evidence  it  is  based,  it  would  be 
well  to  consider  its  genesis  and  briefly  recall  the  ancient 
notions  regarding  "artificial"  light. 

Light  was  first  confused  with  seeing,  and  it  is  said  that 
up  to  the  time  of  Aristotle  men  commonly  thought  they 
saw  by  reason  of  something  shooting  out  from  the  eyes  and 
coming  in  contact  with  objects;  the  converse  of  the  Carte- 
sian conception  of  many  centuries  later,  that  certain  move- 
ments in  bodies  cause  them  to  shoot  out  minute  particles  in 
all  directions,  which,  striking  the  eye  or  causing  "glob- 
ules" of  air  to  strike  it,  excite  vision. 

The  fluid  nature  of  fire  and  the  corporeal  nature  of  light, 
which  were  believed  in  throughout  the  early  and  middle 
ages,  seem  to  have  been  first  doubted  by  Sir  Francis  Bacon 
about  the  end  of  the  sixteenth  century,  although  he  was  by 
no  means  sure  that  these  conceptions  were  wrong.  Bacon 
classed  together  the  light  from  flames,  decayed  wood,  glow- 
worms, silks,  polished  surfaces,  etc.,  and  said  that  inas- 
much as  some  animals  can  see  in  the  dark,  air  has  some 
light  of  itself.  Boerhaave,  somewhat  later,  also  expressed 
doubts  as  to  the  substantive  nature  of  fire. 


WHY  A  FLAME  EMITS  LIGHT  91 

.  Among  the  first  recorded  experiments  upon  the  nature 
and  action  of  luminous  flames  are  those  which  were  carried 
out  by  Sir  Robert  Boyle  between  1660  and  1670.  He  at- 
tempted to  prove  by  experiment  whether  the  light  from,  a 
flame  is  like  that  from  the  sun,  and  whether  it  is  corporeal 
or  merely  a  quality.  He  allowed  a  flame  to  play  on  metals 
directly  and  also  when  in  open  and  sealed  vessels,  and  be- 
cause the  substance  formed  a  calx  and  gained  in  weight,  he 
thought  that  the  light  or  flame  (he  uses  the  term  indiscrim- 
inately) had  combined  with  the  metal,  and  hence  it  must  be  a 
fluid.  Boyle  also  conducted  a  large  number  of  experiments 
upon  live  or  "quick"  coals,  phosphorescent  bodies,  animals 
and  insects  to  see  the  effect  of  exhausting  a  receiver  in  which 
they  were  placed,  and  he  seems  to  have  concluded  that  the 
lights  from  live  coals,  rotten  wood  and  putrefying  fish  differ 
not  in  kind  but  only  in  degree.  He  considered  that  the 
increase  of  light  from  coals,  etc.,  and  the  reviving  of  certain 
insects  when  air  was  readmitted  to  the  receiver  indicated  a 
relation  between  a  visible  flame  and  the  so-called  "  vital 
flame."  But  he  would  not  commit  himself  upon  the  ques- 
tion of  the  supposed  kinship  between  the  '  *  flame ' '  from  live 
coals  and  rotten  wood  and  the  "vital  flame"  thought  to  be 
burning  in  the  hearts  of  all  living  beings. 

The  interesting  views  of  Sir  Isaac  Newton  are  set  forth 
in  a  number  of  queries  published  in  his  work  entitled 
Optics.  As  is  well  known,  Newton  believed  in  the  ma- 
terial nature  of  light,  and  he  asserted  that  the  change  of 
light  into  matter  and  of  matter  into  light  is  an  acknowl- 
edged possibility  and  of  common  occurrence.  He  attributed 
the  light  which  appears  when  a  body  is  rapidly  and  repeat- 
edly struck  or  when  heated  beyond  a  certain  point,  as  when 
flint  and  steel  are  struck  together,  etc.,  to  vibrations  of  the 
parts  of  the  body  so  rapid  as  to  throw  off  the  particles 
which,  according  to  Newton's  idea,  occasion  the  sensation 
of  light.  With  these  he  also  classed  electric  sparks,  saying 
that  the  "electric  vapor"  excited  by  rubbing  glass  dashes 
against  a  strip  of  paper  or  the  end  of  the  finger  held  to  it, 


92  MODERN  SCIENCE  READER 

is  thereby  so  agitated  as  to  cause  it  to  emit  light.  He 
thought  the  light  from  glowworms  and  putrefying  matter 
was  of  the  same  kind  as  the  above,  and  said  that  the  light 
seen  at  night  in  the  eyes  of  certain  animals,  cats  for  in- 
stance, is  "due  to  vital  motions." 

Regarding  true  luminous  flames  Newton's  ideas  were 
nearer  those  of  the  present  time.  He  wrote  "Is  not  fire  a 
body  heated  so  hot  as  to  emit  light  copiously?  For  what 
else  is  a  red-hot  iron  than  fire?  And  what  else  is  a  burn- 
ing coal  than  red-hot  wood ? "  "Is  not  flame  a  vapor,  fume 
or  exhalation  heated  red  hot,  that  is,  so  hot  as  to  shine? 
For  bodies  do  not  flame  without  emitting  a  copious  fume, 
and  this  fume  burns  in  the  flame.  Metals  in  fusion  do  not 
flame  for  want  of  a  copious  fume."  "All  fuming  bodies, 
as  oil,  tallow,  wax,  wood,  etc.,  by  fuming  waste  and  vanish 
into  burning  smoke."  "Put  out  the  flame  and  the  smoke 
is  visible,  it  often  smells;  and  the  nature  of  the  smoke 
determines  the  color  of  the  flame."  "Smoke  passing 
through  flame  cannot  but  grow  red  hot,  and  red-hot  smoke 
can  have  no  other  appearance  than  that  of  flame." 

During  the  hundred  years,  more  or  less,  following  the 
publication  of  Newton's  views  there  was  little  change  in 
the  prevailing  theories.  Stahl  said  "flame  is  light"  liber- 
ated from  bodies  in  the  act  of  combustion,  and  that  light 
and  heat  are  the  constant  attendants  of  fire ;  fire  combined 
with  combustible  matter  was  "phlogiston."  Scheele  held, 
however,  that  light,  heat  and  fire  are  combinations  of  air 
and  "phlogiston."  Lavoisier  thought  flame  to  be  light 
disengaged  from  air,  with  which  it  had  been  in  combina- 
tion, and  this  idea  seems  to  have  been  adopted  by  most 
of  the  French  chemists. 

There  might  be  mentioned  in  this  connection  the  queer 
ideas  regarding  our  being  able  to  see  objects,  and  the  emis- 
sion of  light  by  incombustible  bodies,  which  were  held 
during  the  latter  half  of  the  eighteenth  century.  As  ex- 
pressed by  Macquer,  and  quoted  by  Fourcroy,1  ' '  The  vibra- 
to ureroy's  Chemistry,  press  date  1796.  • 


VTHY  A  FLAME  EMITS  LIGHT  93 

tions  (under  the  impulse  of  more  or  less  heat)  dispose  the 
particles  (of  bodies)  in  such  a  manner  that  their  faces, 
acting  like  so  many  little  mirrors,  reflect  upon  our  eyes  the 
rays  of  light  which  are  in  the  air  by  night  as  well  as  by 
day;  for  we  are  involved  in  darkness  during  the  night  for 
no  other  reason  but  because  they  are  not  then  so  directed 
as  to  face  our  organs  of  sight." 

At  a  single  step  we  pass  from  the  rather  crude  ideas  of 
the  older  thinkers  to  those  ideas  which  obtain  at  the  present 
day,  and  the  transition  finds  little  expression  in  the  litera- 
ture. 

About  the  year  1816  Sir  Humphry  Davy  advanced  what 
has  been  known  ever  since  as  the  " solid  particle"  theory 
of  luminosity ;  a  theory  which  went  unchallenged  for  forty- 
five  years  and  was  accepted  by  practically  every  one. 

He  was  experimenting  upon  the  combustion  taking  place 
in  his  famous  safety  lamp  and  said,  "I  was  led  to  imagine 
that  the  cause  of  the  superiority  of  the  light  of  a  stream 
of  coal  gas  might  be  owing  to  the  decomposition  of  a  part 
of  the  gas  toward  the  interior  of  the  flame,  where  the  air 
is  in  smallest  quantity,  and  the  deposition  of  solid  charcoal, 
which,  first  by  its  ignition  and  afterward  by  its  combus- 
tion, increased  to  a  high  degree  the  intensity  of  the  light ; 
and  a  few  experiments  soon  convinced  me  that  this  was  the 
true  solution  of  the  problem."  ''Whenever  a  flame  is 
remarkably  brilliant  and  dense,  it  may  always  be  concluded 
that  some  solid  matter  is  produced  in  it;  on  the  contrary, 
whenever  a  flame  is  extremely  feeble  and  transparent  it 
may  be  inferred  that  no  solid  matter  is  formed."  The 
idea  that  solid  carbon  in  the  flame  is  the  source  of  its  light 
was  not  original  with  Davy— he  says  it  was  suggested  by 
a  Mr.  Hare— but  it  was  Davy's  investigations  which  put  it 
on  a  firm  basis  and  he  formulated  the  theory. 

Davy  showed  the  relation  between  the  heat  and  light  of 
flames,  the  effects  of  rarefaction  and  compression  of  the 
surrounding  air  and  the  influence  of  cooling  and  heating. 
He  pointed  out  also  that  a  luminous  flame  will  deposit  car- 


94  MODERN  SCIENCE  READER 

bon  on  a  cold  surface,  and  if  rendered  non-luminous  no 
carbon  can  be  obtained.  These  conclusions  were  imme- 
diately accepted  and  were  not  seriously  disputed  until  the 
appearance  in  1861  of  a  communication  to  the  Royal  Society 
from  E.  Frankland. 

In  this  article  Frankland  advanced  what  has  come  to  be 
known  as  the  "dense  vapor"  theory.  He  and  his  adherents 
claimed  that,  although  solid  particles  in  a  flame  do  cause  it 
to  emit  light,  the  light  from  our  ordinary  illuminating 
flames  is  dependent  to  a  great  extent  upon  the  presence  of 
dense,  transparent,  hydrocarbon  vapors  from  which  it  is 
radiated,  and  is  not  due  to  the  presence  of  incandescent 
solid  carbon  particles.  They  further  claimed  that  the  soot 
deposited  is  not  carbon,  but  a  mixture  of  dense  hydrocar- 
bons of  remarkably  high  boiling  points. 

Frankland  was  led  to  take  up  his  investigations  by  seeing 
a  report  that  candles  burned  at  the  same  rate  on  the  top  of 
Mt.  Blanc  as  in  the  valley  at  its  foot,  and  a  second  report 
regarding  the  retardation  of  the  bursting  of  shells  with 
time  fuses  at  high  elevations  in  India. 

Besides  carrying  on  investigations  in  artificially  rarefied 
air  in  his  laboratory,  he  climbed  to  the  top  of  Mt.  Blanc 
with  a  goodly  supply  of  standard  candles  and  timed  their 
slow  wasting  away;  probably  keeping  warm  in  the  mean- 
time by  the  fire  of  his  enthusiasm.  Many  interesting  facts 
were  brought  to  light  by  these  investigations,  but  his  use  of 
them  in  interpreting  the  causes  of  luminosity  in  ordinary 
flames  led  him  into  error,  and,  although  he  found  adherents 
at  the  time,  his  views  have  long  since  been  replaced  by  those 
based  upon  more  careful  observation.  The  importance  of 
the  work  of  Frankland  lay  not  so  much  in  what  he  did  as 
in  what  he  led  others  to  do ;  and  since  the  publication  of  his 
views  a  great  deal  has  been  done  by  Heumann,  Stein, 
Smithells,  Burch,  Lewes  and  others. 

Stein  disproved  Frankland 's  assertion  that  soot  is  a  mix- 
ture of  dense  hydrocarbons  by  showing  that  it  cannot  be 
volatilized  even  by  great  heat,  and  that  it  contains  only 


WHY  A  FLAME  EMITS  LIGHT  95 

about  nine  tenths  of  one  per  cent,  of  hydrogen,  which  can 
be  separated  from  it  only  at  high  temperatures  in  an 
atmosphere  of  chlorine. 

Is  or  did  Frankland's  view  that  glowing,  dense  vapors 
cause  the  light  appeal  to  Heumann,  who  thought  it  unlikely 
that  such  dense  vapors  exist  in  a  flame  or  that  there  is  a 
sufficiently  high  temperature  to  cause  them  to  glow.  He 
knew,  of  course,  that  at  a  temperature  like  that  of  an 
electric  arc  many  gases  do  glow  and  give  continuous  spectra, 
and  that  a  highly  heated  gas  under  pressure  acts  likewise ; 
but  he  argued  that  if  carbon  really  does  exist  as  such  in  a 
flame,  it  most  probably  is  the  source  of  luminosity.  To 
prove  its  presence  or  absence  he  studied  the  effects  upon  a 
flame  of  heating  and  cooling  it,  of  diluting  and  varying 
the  temperature  of  the  gases  supplied  to  it,  its  transparency 
and  the  shadows  cast  by  it,  as  well  as  other  phenomena ;  and 
the  results  of  his  experiments  led  him  to  give  unqualified 
support  to  the  theory  of  Davy. 

Some  account  of  the  salient  features  at  least  of  Heu- 
mann's  elaborate  investigation  must  be  given  in  order  to 
convey  any  idea  of  his  part  in  firmly  fixing  the  "  solid 
particle"  theory.  By  allowing  a  luminous  flame  to  play 
upon  a  surface  which  rapidly  conducted  heat  away  from 
it,  like  a  platinum  dish,  its  luminosity  was  destroyed.  Heat- 
ing the  upper  surface  of  the  dish  restored  the  luminosity, 
and  hence  Heumann  concluded  that  cooling  a  flame  dimin- 
ishes its  light-giving  properties,  while  heating  increases 
them.  He  varied  the  temperature  of  illuminating  gas  be- 
fore it  reached  the  burner  and  found  that  the  same  effects 
were  produced.  The  heating  in  some  cases  increased  the 
normal  light-giving  power  as  much  as  a  hundred  and 
twenty-five  per  cent.  Further  investigation  showed  that 
luminosity  can  also  be  diminished  or  destroyed  by  rapid 
oxidation  of  the  hydrocarbons,  as  well  as  by  diluting  them 
with  a  neutral  gas  like  nitrogen  or  carbon  dioxide;  the 
effect  of  dilution  being  to  necessitate  a  higher  tempera- 
ture for  luminosity.  He  next  rendered  a  flame  non-lumi- 


96  MODERN  SCIENCE  READER 

nous  by  cooling,  introduced  chlorine  into  it  to  break  down 
the  hydrocarbons,  and  obtained  a  brilliant  light.  A  porce- 
lain rod  introduced  into  the  lower  part  of  a  flame  cooled  it 
and  decreased  its  light,  but  collected  no  carbon,  while,  if 
introduced  into  the  upper  part,  its  under  side  became  coated 
with  soot.  Heumann  argued  that  if  Frankland  was  right 
and  the  light  is  reflected  from  dense  hydrocarbon  vapors, 
these  should  be  condensed  on  all  sides  of  the  rod  at  once  in 
a  quiet  flame,  while,  as  a  matter  of  fact,  soot  was  deposited 
only  on  the  under  side;  and  furthermore,  soot  can  also  be 
collected  upon  a  surface  too  hot  to  condense  hydrocarbons 
at  all.  He  therefore  concluded  that  the  surface  merely 
stops  carbon  which  is  formed  lower  down  in  the  flame.  If 
one  luminous  flame  is  allowed  to  play  against  another,  the 
carbon  is  rolled  up  and  can  be  seen  as  glowing  particles  in 
the  outer  non-luminous  sheath. 

Frankland  had  said  that  flames  cannot  contain  solid 
particles  because  they  are  transparent.  Heumann  pointed 
out  that  thick  flames  are  opaque  and  that  thin  ones  are  no 
more  transparent  than  is  an  equal  layer  of  soot  rising  from 
burning  turpentine ;  the  rapidity  of  the  motion  of  the  par- 
ticles preventing  any  obstruction  to  the  view,  just  as  is  the 
case  with  a  rapidly  revolving,  spoked  wheel. 

Heumann  next  took  up  the  phenomena  of  shadows  and 
showed  that  the  luminous  portion  casts  a  definite  shadow 
when  interposed  between  sunlight  and  a  screen,  and  that 
the  shadow  is  continuous  for  a  luminous  turpentine  flame 
and  the  column  of  soot  above  it.  And  further,  that  a 
hydrogen  flame  which  ordinarily  casts  no  shadow  and  gives 
no  light  will  cast  a  sharp  shadow  and  emit  a  fairly  bright 
light  if  passed  through  suspended  lampblack  or  if  it  sweeps 
any  solid  matter  into  the  flame.  Luminous  vapors  do  not 
cast  shadows,  absorption  bands  being  very  different  from 
true  shadows. 

C.  J.  Burch  found  that  when  sunlight  is  reflected  from 
a  luminous  flame  it  is  polarized,  while  if  reflected  by  glow- 
ing vapors,  however  dense,  it  does  not  exhibit  this  phe- 


WHY  A  FLAME  EMITS  LIGHT  97 

nomenon.  Sunlight  which  was  reflected  and  refracted  by 
luminous  flames  was  found  to  exhibit  phenomena  identical 
with  that  reflected  and  refracted  by  non-luminous  flames 
rendered  luminous  by  the  introduction  of  solid  matter, 
and  also  with  light  reflected  and  refracted  by  very  finely 
divided  solid  matter  held  in  suspension  in  a  liquid.  The 
phenomena  presented  by  like  experiments  with  glowing 
vapors  were  totally  different.  All  of  Bureh's  work  was 
confirmed  by  Stokes  some  years  later. 

There  was  now  left  no  shadow  of  doubt  about  carbon 
being  the  source  of  the  light  rays,  and  the  next  question 
that  concerned  investigators  was  the  chemical  changes 
which  give  rise  to  carbon  particles. 

Sir  Humphry  Davy  thought  the  separation  of  carbon 
to  be  due  to  a  decomposition  of  the  hydrocarbon  compounds 
(of  which  all  illuminants  are  composed)  within  the  flame 
where  the  air  is  in  smallest  quantity,  and  no  other  cause 
was  assigned  by  other  investigators.  Prior  to  1861  the 
view,  it  seems,  was  that  carbon  is  liberated  because  of  a 
supposed  greater  affinity  of  oxygen  for  the  hydrogen  of  the 
hydrocarbon  than  for  the  carbon,  there  not  being  enough 
for  both.  But  these  points  had  to  be  tested. 

In  the  study  of  the  chemical  changes  that  take  place,  a 
flame  burning  at  a  circular  orifice  offered  the  best  condi- 
tions. As  explained  in  text-books  of  chemistry,  such  a 
flame  may  be  thought  of  as  being  made  up  of  an  inner, 
faintly  luminous  cone  fitting  into  an  outer,  brightly  lumi- 
nous one— as  a  finger  fits  into  a  glove  finger— this  latter 
being  surrounded  by  a  non-luminous  sheath  of  water  vapor 
and  carbon  dioxide.  It  was  desirable  to  separate  these 
two  cones,  in  order  to  study  the  gas  after  it  had  left  the 
inner  cone  and  before  any  change  had  been  brought  about 
by  the  conditions  existing  in  the  outer  cone.  This  separa- 
tion was  first  accomplished  by  Techlu,  in  France,  and 
Arthur  Smithells,  in  England,  working  independently, 
with  a  piece  of  apparatus,  the  essential  features  of  which 
are  pictured  in  cross  section  in  Fig.  1.  By  a  proper  con- 
7 


98 


MODERN  SCIENCE  READER 


trol  of  the  relative  proportions  of  gas  and  air  the  inner 
cone  was  made  to  burn  at  the  orifice  i,  while  the  outer  cone 
burned  at  the  orifice  o.  The  outer  cone  got 
its  oxygen  from  the  surrounding  air,  while 
that  for  the  lower  flame  was  supplied  along 
with  the  gas.  The  temperature  of  each 
cone  was  measured  and  the  gases  entering 
and  leaving  each  were  analyzed.  It  was 
Q  found  that  as  the  proportion  of  gas  to  air 
was  increased,  the  tip  of  the  inner  or  lower 
cone  became  brightly  luminous  and  a  col- 
umn of  soot  passed  upward  through  the 
tube,  becoming  faintly  luminous  in  the 
outer  edge  of  the  upper  flame.  As  soon  as 
the  inner  cone  becomes  luminous  the  un- 
saturated1  hydrocarbon  compound  known, 
as  acetylene  begins  to  appear  among  the 
gases  passing  to  the  outer  cone. 

Vivian  B.  Lewes  now  attacked  the  prob- 
lem as  to  how  carbon  comes  to  be  in  the 
flame  in  the  free  state.  He  analyzed  gas 
drawn  from  different  parts  of  a  coal  gas 
flame,  measured  the  temperature  of  its  dif- 
ferent parts,  etc.,  publishing  his  results  be- 
tween 1892  and  1895.  These  results  may 
be  stated  as  follows:  Coal  gas  consists 
mainly  of  a  mixture  of  hydrogen  and 
hydrocarbons,  both  saturated  and  unsat- 
Tirated.  In  an  ordinary  "fishtail"  burner 
flame  all  hydrogen  is  consumed  before  the 
middle  of  the  luminous  portion  is  reached.  Of  the  satu- 
rated hydrocarbons  about  seventy-five  per  cent,  disappears 
as  such  in  the  dark  portion  and  about  twenty-four  per 

irThe  terms  "  saturated "  and  ' '  unsaturated "  have  reference, 
among  other  things,  to  the  relative  quantity  of  hydrogen  to  carbon 
in  the  molecule,  an  unsaturated  compound  having  relatively  less 
hydrogen  than  a  saturated  one. 


FIG.  1 


WHY  A  FLAME  EMITS  LIGHT  99 

cent,  is  lost  in  the  lower  half  of  the  luminous  part.  In  the 
dark  part  there  occurs  a  transformation  of  saturated  into 
unsaturated  hydrocarbons,  along  with  a  general  breaking 
down  of  all  to  yield  products  less  rich  in  hydrogen  and  the 
oxides  of  carbon.  At  the  point  where  luminosity  just 
begins,  seventy  to  eighty  per  cent,  of  the  unsaturated  com- 
pounds is  acetylene,  although  less  than  one  per  cent,  was 
originally  present.  No  acetylene  could  be  found  in  the 
flame  when  it  was  made  non-luminous. 

By  causing  pure  gases  to  pass  through  tubes  heated  to 
known  temperatures  and  analyzing  the  products  formed, 
Lewes  studied  the  effects  of  heat  upon  both  saturated  and 
unsaturated  hydrocarbons.  At  800°  C.  an  unsaturated 
compound,  like  ethylene,  C2H4,  breaks  down  into  hydrogen 
and  the  still  more  unsaturated  acetylene,  C2H2.  At  1200° 
C.  the  very  stable  saturated  hydrocarbons  decompose  into 
acetylene  and  hydrogen,  and  the  acetylene  in  turn  decom- 
poses into  carbon  and  hydrogen.  Even  very  dense  hydro- 
carbons decompose  at  1200°  C.  These  results  strengthened 
Lewes'  conviction  that  under  the  baking  action  of  the 
flame  walls  in  the  lower  portions  acetylene  is  produced  in 
relatively  large  quantities  and  that  this  is  the  source  of  the 
carbon. 

The  question  which  immediately  presented  itself  was, 
Does  there  exist  in  an  ordinary  flame  such  conditions  of 
temperature  as  may  bring  about  the  formation  of  acetylene 
from  the  very  stable  constituents  of  the  illuminants?  On 
measuring  the  temperatures  at  various  places  the  necessary 
temperatures  were  found  to  exist. 

The  work  was  complete  and  conclusive  and  forced  a 
general  acceptance  of  the  theory  that  acetylene  is  the 
immediate  source  of  the  carbon. 

But  a  yet  harder  problem  presented  itself,  What  gives 
rise  to  heat  sufficient  to  make  the  carbon  become  incandes- 
cent?—a  burning  question  certainly  and  one  not  easy  to 
answer. 

From  the  time  of  Davy  to  the  year  1892  the  only  opinion 


100  MODERN  SCIENCE  READER 

was  that  the  burning  hydrogen,  carbon  monoxide  and 
hydrocarbons  furnished  the  heat  necessary  to  raise  carbon 
to  incandescence.  In  that  year  Lewes  advanced  his  "latent 
heat"  theory.  This  theory  declared  that  the  latent  heat 
set  free  when  acetylene  is  decomposed  instantly  heats  the 
carbon  particles  thus  set  free  to  incandescence. 

After  showing  that  the  heat  of  combustion  of  a  flame  is 
only  sufficient  to  render  carbon  faintly  luminous,  Lewes 
compared  the  temperatures  of  flames  burning  coal  gas,  the 
unsaturated  hydrocarbon  gas,  ethylene,  and  the  still  less 
saturated  acetylene,  and  also  the  amount  of  light  given  by 
each  when  burning  equal  volumes  of  gas  per  hour  from 
burners  best  suited  to  each.  He  likewise  studied  the 
temperatures  developed  when  acetylene  is  exploded  and 
the  localization  of  the  heat  set  free  by  its  decomposition. 
His  experiments  were  ingenious  and  convincing.  By  com- 
paring ethylene,  C2H4,  with  acetylene,  C2H2  (where  for 
equal  consumption  the  same  number  of  carbon  atoms  were 
present),  and  also  with  coal  gas,  it  was  seen  that  the  lumi- 
nous portion  of  the  acetylene  flame  is  not  as  hot  as  that  of 
either  ethylene  or  coal  gas,  while  the  illuminating  powers 
of  the  flames  were :  acetylene,  240.0  candle  power,  ethylene, 
65.5  c.p.  and  coal  gas,  16.8  c.p.  Evidently  the  heat  of 
combustion  does  not  account  for  the  incandescence  of  the 
carbon ;  for  if  it  did  the  cooler  acetylene  flame  would  give 
less  light,  while,  as  a  matter  of  fact,  it  gives  twice  as  much 
as  the  ethylene  and  about  fourteen  times  as  much  light  as 
the  very  much  hotter  coal  gas  flame.  It  was  evident  that 
our  temperature  measuring  instruments  do  not  detect  the 
heat  of  the  carbon  particles  themselves. 

To  see  if  luminosity  be  even  partly  due  to  the  latent  heat 
of  acetylene,  Lewes  exploded  that  gas  in  a  closed  tube. 
This  was  done  by  wrapping  a  bit  of  fulminate  of  mercury 
in  tissue  paper  and  suspending  it  by  copper  wires  joined 
by  platinum  in  contact  with  the  fulminate,  and  passing  an 
electric  current.  There  followed  a  brilliant  flash  of  light 
and  a  complete  decomposition  of  the  gas,  and  of  the  eudio- 


WHY  A  FLAME  EMTT3  LIGHT     K  >>'> 


meter  as  well.  Pieces  of  glass  were  coated  with  carbon, 
and  the  tissue  paper  was  not  scorched  except  in  a  small  hole 
where  the  explosion  of  the  fulminate  had  burst  through. 
This  experiment  showed  the  formation  of  carbon,  the  emis- 
sion of  a  brilliant  light  and  the  localization  of  the  heat 
liberated.  But  as  the  decomposition  in  a  flame  can  hardly 
be  as  rapid  as  in  this  experiment,  and  as  hydrogen  and 
oxygen  also  give  a  feeble  light  when  exploded,  he  sought 
to  detect  the  rise  in  temperature  at  the  moment  of  decom- 
position when  this  is  caused  by  heat.  He  arranged  a 
thermo-couple  in  a  small  tube  so  that  only  the  turn  of 
wires  was  exposed,  and  after  sweeping  out  the  air  passed 
a  slow  current  of  acetylene  through  the  tube,  the  arrange- 


( 

K 

^ 

V 

> 

V 

«- 

( 

/^ 
/• 

> 

1 

V 
1  1  II        1   ' 
—  sm.m.  -* 

A 

ment  being  as  shown  in  Fig.  2.  The  heat  was  raised 
throughout  the  tube  at  a  rate  of  about  10°  C.  per  minute, 
and  almost  as  soon  as  the  temperature  of  area  a  passed 
800°  C.  it  took  a  sudden  leap  to  1000°  C.,  the  gas  burst  into 
a  lurid  flame  and  streams  of  carbon  passed  on  through  the 
tube.  Although  the  temperature  of  area  &  was  made  con- 
siderably higher  than  a  the  carbon  passing  through  it  was 
not  luminous.  This  experiment  would  seem  to  leave  no 
doubt  that  the  incandescence  is  caused  by  latent  heat,  yet 
further  evidence  was  produced.  In  another  experiment 
in  which  diluted  acetylene  was  used  it  required  a  higher 
heat  to  cause  the  decomposition  and  luminosity.  This 
latter  is  the  condition  existing  in  a  flame,  and  the  tempera- 
ture there  found  is  above  that  required.  In  other  experi- 


'102  &£«1S&N  SCIENCE  READER 

ments  it  was  found  that  if  the  flame  temperature  were  high 
enough  the  luminosity  was  directly  proportional  to  the 
amount  of  acetylene  in  the  flame  at  the  point  where  lum- 
inosity generally  begins.  Acetylene  was  introduced  at  the 
corresponding  place  in  a  non-luminous  flame  through  very 
fine  holes  in  a  small  capillary  platinum  tube,  and  the  rate 
of  its  flow,  as  well  as  that  of  the  illuminating  gas,  was 
measured  and  controlled  so  as  to  have  present  the  amount 
of  acetylene,  which  analysis  showed  to  exist  in  a  similar 
luminous  flame.  At  the  holes  there  was  an  intense  light, 
and  dull  red  streams  of  carbon  passed  upward  in  the  flame. 

Lewes  sums  up  his  conclusions,  drawn  from  all  his  work, 
about  as  follows :  When  the  hydrocarbon  gas  leaves  the  jet 
at  which  it  is  burned,  those  portions  which  come  in  con- 
tact with  the  air  are  consumed  and  form  a  wall  of  flame, 
which  surrounds  the  issuing  gases.  The  unburnt  gas  in  its 
passage  through  the  lower  heated  area  undergoes  a  number 
of  chemical  changes,  brought  about  by  the  heat  radiated 
from  the  flame  walls;  the  principal  change  being  the  con- 
version of  hydrocarbons  into  acetylene,  hydrogen  and 
methane.  The  temperature  of  the  flame  rapidly  increases 
with  the  distance  .from  the  jet  and  reaches  a  point  at  which 
it  is  high  enough  to  decompose  acetylene  into  carbon  and 
hydrogen  with  a  rapidity  almost  that  of  an  explosion.  The 
latent  heat  so  suddenly  set  free  is  localized  by  the  proximity 
of  carbon  particles,  which  by  absorbing  it  become  incandes- 
cent and  emit  the  larger  part  of  the  light  given  out  by  the 
flame ;  although  the  heat  of  combustion  causes  them  to  glow 
somewhat  until  they  come  into  contact  with  oxygen  and 
are  consumed.  This  external  heating  gives  rise  to  little  of 
the  light. 

There  have  been  opponents  to  this  theory  of  the  cause 
of  luminosity— as  there  are,  fortunately,  of  all  theories— 
but  the  evidence  is  so  strong  and  covers  so  many  points, 
and  so  many  investigators  have  confirmed  one  part  or 
another  of  the  work,  that  it  has  been  generally  accepted  as 
a  true  statement  of  the  facts  with  which  it  deals. 


MARVELS  OF  A  PLANT'S  GROWTH, 
AND  THE  CHEMISTRY  OF  DECAY1 

EY  PKOFESSOB  VIVIAN  B.  LEWES 

IN  the  whole  of  Nature's  wonder  book  there  is  nothing 
that  appeals  more  to  our  sense  of  the  marvelous  than  the 
way  in  which  all  the  waste  of  animal  and  vegetable  life  is 
converted  by  decay  into  those  simple  compounds,  carbon 
dioxide  and  water  vapor,  which  are  again  used  in  the 
wonderful  processes  by  which  all  forms  of  life  are  synthet- 
ically recreated. 

It  is  the  sun's  rays  which  are  the  mainspring  of  this 
regeneration,  and  the  growth  of  vegetation  is  the  means  by 
which  it  is  brought  about.  All  the  ordinary  forms  of 
plant  in  which  the  green  pigment  known  as  "chlorophyl" 
is  present,  owe  their  growth  to  energy  derived  from  the 
sun,  under  which  the  chlorophyl  contained  in  the  small 
glands  of  the  plant  absorbs  carbon  dioxide  and  water  vapor 
from  the  atmosphere,  while  more  moisture  and  traces  of 
mineral  salts  are  drawn  in  by  the  roots.  Once  absorbed 
the  carbon  dioxide  and  water  vapor  under  the  influence  of 
the  chlorophyl  commence  a  marvelous  series  of  changes, 
which  result  in  the  formation  of  the  first  visible  product, 
the  starch  granules  and  also  sugars,  which  afterward  be- 
come practically  the  food  of  the  plant,  and  are  incorporated 
as  the  cellulose  or  woody  fiber,  of  which  the  solid  portion 
chiefly  consists,  the  completed  reaction  being  of  some  such 
nature  as  that  expressed  by  the  equation— 

Carbon  dioxide+Water  vapor  I  +Sun,g  energy      i  CeHn-     Oxy. 

I  CoHio  05+602 

And  it  is  this  oxygen  so  liberated  in  the  early  days  of  the 

^Journal  of  the  Society  of  Arts,  abstracted  in  Scientific  American 
Supplement. 

103 


104  MODERN  SCIENCE  READER 

world's  creation  which  according  to  some  theorists  formed 
the  atmosphere,  and  has  since  kept  the  oxygen  present  in 
it  a  practically  constant  quantity. 

It  must  be  borne  in  mind,  however,  that,  although  such 
an  equation  is  capable  of  representing  the  sum  of  the 
actions  taking  place,  yet  it  only  in  reality  represents  the 
first  and  final  stages  of  a  series  of  most  wonderful  and 
beautiful  reactions,  the  exact  course  of  which  is  but  little 
understood.  The  fact  that  the  sun's  energy  is  necessary 
to  bring  about  this  reaction  is  made  manifest  by  the  growth 
of  vegetation  when  kept  from  the  light,  when  it  merely 
gives  rise  to  a  few  sickly  and  colorless  shoots  formed  by  the 
plant  food  already  stored  in  the  plant  or  seed,  while  on  the 
other  hand  recent  experiments  have  shown  that  ordinary 
vegetation  can  be  accelerated  in  its  growth  by  the  illumina- 
tion from  certain  forms  of  artificial  light  during  the  hours 
of  darkness. 

Probably  the  first  attempt  to  use  artificial  light  for 
hastening  the  growth  of  plants  was  made  in  1861  by  Herve- 
Magnon,  while  twenty  years  later  Siemens,  by  experiment- 
ing with  an  arc  lamp  of  1,400  candle  power,  placed  ten  feet 
from  the  plants,  with  a  glass  screen  interposed,  came  to  the 
conclusion  that  this  illumination  was  capable  of  producing 
an  effect  equal  to  about  half  that  of  the  sun.  In  more 
recent  years  various  artificial  lights  have  been  employed 
for  accelerating  growth,  and  it  has  been  found  that  nearly 
all  plants,  aided  in  their  development  by  artificial  light  to 
which  they  are  exposed  during  the  usual  hours  of  darkness, 
reached  the  flower  and  fruit  bearing  stage  much  earlier 
than  with  sunlight  alone,  some  few,  however,  like  the  onion, 
declining  to  be  hurried.  That  this  growth  and  progress  is 
not  at  the  expense  of  root  formation  is  abundantly  proved 
in  the  case  of  such  plants  as  radishes,  in  which  not  only  was 
the  top  growth  three  times  that  of  a  similar  plant  growth 
in  sunlight  alone,  but  the  root  growth  also  amounted  to 
two  and  a  half  times  the  normal  in  a  given  time. 

From  the  exhaustive  researches  which  have  been  made 


PLANT'S  GROWTH  AND  DECAY  105 

upon  plant  life,  it  seems  fairly  clear  that  the  function  of 
the  chlorophyl  in  the  growing  plant  is  practically  three- 
fold. It  has  been  shown  that  it  is  those  rays  in  the  imme- 
diate neighborhood  of  the  red  and  orange  in  the  spectrum 
which  most  keenly  excite  the  assimilation  of  carbon  dioxide 
and  water  vapor,  and  that  the  chloropyhl  absorbs  those  rays 
which  hinder  the  formation  of  carbohydrates,  transform- 
ing rays  of  short  wave  lengths  into  those  rays  which  most 
favorably  effect  the  production  of  the  sugars  and  starch, 
which  are  the  food  of  the  plant  structure,  and  that  it  also 
acts  by  the  conversion  of  light  into  heat. 

The  usual  statement  that  the  solid  matter  of  the  plant 
consists  of  cellulose  is,  of  course,  only  an  approximation  to 
the  truth,  as  cellulose  is  only  one  of  several  modifications 
produced  by  the  actions  taking  place  in  the  growth  of  the 
plant ;  but  as  from  a  calorific  point  of  view  the  other  organic 
bodies  present  have  practically  the  same  thermal  value,  it 
is  a  convenient  simplification  to  take  wood  as  being  com- 
posed of  cellulose,  water,  and  the  constituents  of  the  sap, 
mineral  salts  and  extractive  matters,  which  may  be  resinous 
(as  in  coniferous  woods),  extractive  (as  in  beech  or  birch) 
.or  tannin  (as  in  oak). 

The  chemical  actions  which  have  resulted  in  the  forma- 
tion of  the  cellulose  have  required  an  expenditure  of 
energy  which,  in  the  primary  decomposition  of  the  carbon 
dioxide  and  w-ater  vapor,  can  be  expressed  in  terms  of  the 
heat  necessary  to  raise  a  unit  weight  of  water  one  degree. 

As  in  the  growth  of  the  plant  this  energy  has  been  de- 
rived from  the  sun,  and  has  been  partially  rendered  latent 
in  the  cellulose,  when  we  burn  that  compound  in  the  form 
of  wood  so  as  again  to  convert  the  carbon  and  hydrogen  to 
carbon  dioxide  and  water  vapor,  we  once  more  set  free  the 
stored  energy  in  the  form  of  heat  and  can  render  it  avail- 
able for  heating  purposes  or  for  doing  work. 

The  variations  in  the  physical  properties  of  wood  are 
dependent  upon  the  constituents  of  the  sap  and  the  density 
with  which  the  solid  matter  is  packed  away  in  the  struc- 


106  MODERN  SCIENCE  READER 

ture,  and  when  the  wood  comes  to  be  burnt  its  calorific  value 
is  found  to  vary  slightly  owing  to  these  factors,  and  also  to 
the  amount  of  moisture  which  it  contains ;  as  upon  the  con- 
stituents of  the  sap  will  largely  depend  the  amount  of  ash 
which  is  formed,  and  upon  the  moisture  the  amount  of 
heat  which  will  be  rendered  latent  in  the  conversion  of  the 
water  into  steam.  Moreover,  in  the  formation  of  the  cellu- 
lose oxygen  equivalent  in  quantity  to  that  which  was  orig- 
inally in  combination  with  the  hydrogen  will  have  been 
again  taken  into  combination  in  the  formation  of  the  plant's 
structure,  with  the  result  that  air-dried  wood,  when  tested 
for  its  calorific  value,  is  but  a  poor  fuel. 

The  moisture  present  in  a  sample  of  wood  will  vary 
enormously  with  the  time  of  year  at  which  the  tree  has 
been  cut  down,  and  also  with  the  nature  of  the  tree,  so  that 
while  as  little  as  eighteen  per  cent,  of  moisture  has  been 
found  in  one  kind  of  wood,  it  may  exceed  fifty  per  cent,  in 
another,  while,  under  the  most  favorable  conditions,  air 
drying  will  only  reduce  the  moisture  in  wood  to  form 
eighteen  to  twenty  per  cent.  It  may,  therefore,  be  roughly 
stated  that  at  the  best,  wood  will  only  contain  eighty  per 
cent,  of  combustible  matter,  while  the  large  amount  of  heat 
absorbed  in  heating  and  evaporating  the  water  present  is 
a  serious  drawback  to  it  as  a  fuel. 

The  combined  oxygen  also  present  in  the  cellulose,  as  has 
been  before  indicated,  seriously  detracts  from  its  value, 
and  where  wood  is  the  only  fuel  that  can  be  employed, 
and  great  local  heat  is  required,  a  fuel  of  practically  double 
the  value  of  wood  can  be  obtained  by  its  conversion  into 
charcoal  before  use.  Under  the  influence  of  destructive 
distillation  the  contained  moisture  and  combined  oxygen 
are  drivrn  forth  as  water  vapor ;  and  although  four  fifths 
of  the  weight  of  the  wood  is  lost  in  the  liquid  and  gaseous 
products  escaping,  yet  the  twenty  per  cent,  of  carbon  that 
remains  on  burning  is  free  from  the  drawback  of  having 
the  intensity  of  the  heat  of  combustion  lowered  by  the 
rendering  latent  of  heat,  which,  in  the  case  of  wood,  was 


PLANT'S  GROWTH  AND  DECAY  107 

lost  in  vaporizing  the  water  and  bringing  about  the  decom- 
position. 

In  the  same  way  that  human  beings  and  animals  of  the 
present  day  are  of  a  very  different  and  higher  type  to 
those  which  first  appeared  on  the  earth's  surface,  so  our 
plant  life  has  undergone  a  great  alteration  in  character, 
and  as  we  trace  by  the  light  of  geology  the  birth  and 
growth  of  vegetation,  we  are  led  to  the  conclusion  that  as 
the  earth  cooled  down,  soil  was  first  formed  upon  its  rock 
surface  by  the  disintegrating  action  of  water  containing 
carbon  dioxide  and  by  those  processes  to  which  we  usually 
give  the  name  of  "weathering."  Spores  of  the  lower 
forms  of  plants,  like  lichens  and  mosses,  then  appeared, 
and  in  their  growth  fixed  the  carbon  and  hydrogen  from 
the  carbon  dioxide  and  water  vapor  to  the  atmosphere.  By 
their  decomposition  they  supplied  the  soil,  which  up  to  that 
time  had  been  of  a  purely  mineral  character,  with  the 
organic  constituents  necessary  for  the  growth  of  vegetation 
of  a  higher  order. 

This  next  form  of  vegetation,  urged  on  in  its  growth  by 
the  heat  permeating  from  the  cooling  mass  of  the  earth, 
and  fed  by  the  excess  of  carbon  dioxide  and  moisture  in 
the  air  and  the  virgin  soil  in  which  it  grew,  attained  a 
rapidity  and  luxuriance  of  growth  which  probably  has 
never  been  equaled.  In  type  it  consists  chiefly  of  crypto- 
gamic  plants,  such  as  club  mosses,  sedges,  and  other  forms 
of  marsh  vegetation,  which,  however,  instead  of  growing 
to  a  height  of  a  few  inches,  attained  enormous  dimensions. 
Dying  down  year  by  year  they  formed  a  densely  packed 
mass  of  vegetable  matter,  which  undergoing  the  process  of 
checked  decomposition  of  the  same  character  as  can  be 
recognized  in  the  peat  deposits  of  the  present  day,  gradually 
built  up  those  masses  of  semi-decomposed  vegetable  matter 
which  were  afterward  converted  by  time,  heat,  and  pres- 
sure into  the  coal  seams. 

The  formation  of  peat  is  apparently  due  partly  to  fer- 
mentation when  exposed  in  its  wet  state  to  air,  and  partly 


108  MODERN  SCIENCE  READER 

to  checked  decay  when  covered  with  water,  and  it  is  the 
latter  process  which  is  the  most  valuable  in  converting  it 
into  a  form  which  is  available  for  fuel. 

When  decomposing  matter  is  freely  exposed  to  moist  air, 
processes  of  fermentation  and  still  further  oxidation  con- 
vert it  ultimately  into  carbon  dioxide  and  water  vapor, 
leaving  as  a  residue  only  the  mineral  matters  and  more 
resistant  hydrocarbons,  the  latter  in  turn  also  disappearing, 
and  it  is  by  such  processes  of  decay  that  Nature  cleanses 
the  surface  of  the  earth  from  all  waste  vegetable  matter. 
When,  however,  the  dead  vegetation  has  its  decay  checked 
by  immersion  in  water  or  the  deposition  over  it  of  silt  or 
soil  of  such  a  character  as  to  cut  off  from  it  the  supply  of 
atmospheric  oxygen,  the  processes  of  decay  continue,  but 
instead  of  exterior  oxygen  acting  on  the  decomposing 
molecules,  the  changes  that  take  place  are  restricted  to 
those  set  up  between  the  constituents  of  the  molecule  itself, 
and  result  in  the  elimination  of  carbon  dioxide,  water,  and 
methane,  with  consequent  lowering  of  the  proportion  of 
hydrogen  and  oxygen  left  in  the  residue. 

Enormous  areas  of  peat  exist  at  the  present  day  not 
only  in  the  British  Isles,  but  in  even  greater  quantities  in 
Russia,  Sweden,  Norway,  Germany,  and  Finland,  while  in 
Canada  and  America  the  peat  bogs  are  still  more  vast,  and 
in  the  future  this  material  will  probably  play  an  important 
part  in  the  supply  of  fuel  when  the  depletion  of  our  coal 
supplies  drives  us  to  utilize  these  natural  stores. 

The  great  interest,  however,  attaching  to  peat  at  the 
present  moment  is  that  the  same  action  which  converts 
cellulose  into  peat  will,  if  continued  under  conditions  of 
considerable  pressure  and  higher  temperatures  than  ordi- 
narily exist  at  the  present  clay,  convert  the  peat  deposits 
into  a  coal  seam. 

Taking  the  luxuriant  vegetation  of  the  carboniferous  era, 
it  is  easy  to  imagine  the  way  in  which  the  huge  peat  bogs 
were  formed  in  the  low-lying  watersheds,  and  in  which  the 
agglomeration  of  vegetable  matter  swept  down  by  the  hur- 


PLANT'S  GROWTH  AND  DECAY 


109 


rying  streams  accumulated  in  the  deltas  of  the  prehistoric 
rivers,  while  the  volcanic  actions  which  marked  this  period 
would  often  cause  so  great  an  alteration  in  the  earth  level 
that  the  decomposing  vegetable  matter  became  subject  to 
the  inrush  of  water  bearing  with  it  huge  quantities  of  mud 
and  silt,  which,  depositing  above  the  collected  vegetation, 
gradually  hardened  there  and  formed  the  strata  which  we 
find  above  the  coal. 

Nor  were  these  actions  confined  to  that  particular  period 
to  which  we  look  back  as  the  carboniferous  age.  We  find 
that  whenever  the  conditions  were  favorable  for  the  deposi- 
tion of  great  beds  of  vegetable  matter,  actions  of  a  similar 
nature  have  led  to  its  conversion  into  coal  in  strata  of  a 
more  modern  character,  and  the  formation  of  coal  appears 
to  have  been  going  on  ever  since  the  inception  of  vegetable 
life  on  the  earth's  surface,  and  there  is  no  reason  to  doubt 
that  the  swamps  and  bogs  of  the  sub-tropical  forests  of  the 
present  day  are  to  a  minor  extent  carrying  on  the  early 
stages  of  the  same  action. 

The  chemical  actions  that  took  place  during  the  period 
when  the  peat  deposits,  heated  from  below  by  the  earth's 
temperature  and  pressed  on  by  the  superincumbent  deposits 
above  them,  underwent  those  changes  in  composition  which 
we  now  recognize  in  our  coal,  can  be  traced  by  analysis,  and 
the  following  table  indicates  the  way  in  which  the  gradual 

THE   CONVERSION   OF  WOODY  FIBER  TO   COAL 

(Butterfield) 


Carbon 

Hydrogen 

Oxygen 

s 

Sulphur 

1 

Cellulose  

44  4 

6  2 

49  4 

4  85 

6  0 

43  5 

0  5 

1  5 

58  0 

6  3 

30  8 

0  9 

4  0 

67  0 

5  1 

19  5 

1  i 

1  0 

6  3 

Coal  .  .                   

77  0 

5  0 

7  0 

1  5 

1  5 

8  0 

Anthracite  

9.00 

2  5 

0  25 

0  5 

0  5 

4  0 

110  MODERN  SCIENCE  READER 

elimination  of  the  hydrogen  and  oxygen  altered  the  cellu- 
lose of  the  growing  plant  to  the  product  of  our  coal  seams. 
This  action  is  made  even  more  manifest  by  calculating 
the  analyses  so  that  the  carbon  is  kept  as  a  fixed  quantity, 
which  brings  into  bold  relief  the  gradual  elimination  of  the 
other  constituents  of  the  cellulose. 

THE  CONVERSION  OF  WOODY  FIBER  TO  COAL 

(Percy) 

Hydro- 
Carbon  gen  Oxygen 

Wood 100  12.18  88.07 

Peat    100  9.85  55.67 

Lignite    100  8.37  42.42 

Bituminous  coal   100  6.12  21.23 

Anthracite    (Wales)     100  4.75  5.28 

Anthracite   (Penna.) 100  2.84  1.74 

Graphite     100  0.00  0.00 

These  changes  in  composition  may  also  be  traced  in  the 
calorific  value,  and  show  the  thermal  advantages  gained  by 
the  elimination  of  the  oxygen  during  these  processes  of 
natural  distillation. 

British  Thermal 

Calories  Units 

Wood 4,771  8,588 

Peat   (dry)    5,600  10,080 

Lignite   7,000  12,600 

Bituminous  coal    8,446  15,203 

Anthracite    8,677  15,618 

It  is  not,  however,  time  alone  which  causes  alteration  in 
the  character  of  coal.  The  factors  of  temperature  and 
pressure  also  play  so  important  a  part  in  its  composition 
that  it  is  unsafe  to  base  any  far-reaching  ideas  as  to  the 
age  of  a  coal  upon  the  amount  of  natural  carbonization 
which  it  has  undergone.  One  may  look  upon  coal  as  con- 
sisting of  a  basis  of  carbon  together  with  the  mineral  mat- 
ters that  were  mostly  present  in  the  sap  of  the  plant,  and 
on  the  combustion  of  the  coal  will  remain  behind  as  ash, 
these  forming  the  solid  residue  which  is  left  on  heating  the 


PLANT'S  GROWTH  AND  DECAY  111 

coal  out  of  contact  with  air.  The  portion  which  under 
these  conditions  escapes,  and  may  therefore  be  termed  the 
volatile  matter,  consists  of  various  compounds  of  carbon 
and  hydrogen  and  other  more  complex  bodies  containing 
not  only  these  elements,  but  also  the  oxygen  and  nitrogen 
present  in  the  coal. 

The  proportion  of  volatile  matter  present,  consisting  as 
it  does  largely  of  hydrocarbons,  makes  a  wonderful  differ- 
ence in  the  way  in  which  a  coal  burns,  the  presence  of 
hydrogen  and  lower  members  of  the  hydrocarbon  series 
giving  the  coal  ease  of  ignition  and  the  property  of  burning 
with  flame,  while  the  more  complex  hydrocarbons  and 
organic  bodies  render  the  flame  so  produced  heavy  and 
smoky  in  its  character.  If  a  coal  which  contains  a  very 
small  percentage  of  volatile  matter,  such  as  anthracite,  be 
taken,  it  is  found  difficult  to  ignite  and  almost  impossible 
to  burn  without  specially  arranged  conditions  of  draft, 
while  the  more  bituminous  coals,  such  as  cannel,  can  be 
ignited  by  the  flame  of  a  match,  and  will  burn  with  the 
greatest  ease. 

With  the  increase  in  bituminous  matter  in  the  coal,  the 
fixed  carbon  or  coke  left  on  distillation  naturally  decreases 
in  quantity,  and  coals  are  generally  classified  on  the  basis 
of  the  amount  of  fixed  carbon  they  contain,  into  lignites, 
cannels,  bituminous  coal,  steam  coal  or  semi-bituminous 
coal,  and  anthracite,  the  percentage  of  carbon  varying  from 
sixty-five  per  cent,  in  some  lignites  up  to  over  ninety  per 
cent,  in  the  anthracites.  The  relation  existing  between  the 
composition  of  the  coal  and  its  powers  of  smoke  production 
is  one  that  will  have  to  be  discussed  again  in  considering 
the  fitness  of  fuels  for  the  class  of  work  they  have  to 
perform. 

Any  form  of  bituminous  coal  when  subjected  to  a  raised 
temperature  begins  to  yield  products  of  a  liquid  and  gas- 
eous character ;  and  if  the  temperature  be  kept  at  the  lowest 
point  at  which  any  action  can  take  place,  the  liquid  distil- 
lates formed  are  of  an  oily  character  and  not  greatly  dis- 


112  MODERN  SCIENCE  READER 

similar  to  some  crude  mineral  oils.  Indeed,  it  seems  highly 
probable  that  when  the  coal  has  been  formed  under  condi- 
tions where  no  escape  of  gaseous  matter  could  take  place 
owing  to  the  impermeability  of  the  low-lying  strata,  a 
natural  distillation  at  very  low  temperature  has  gone  on 
over  long  ages  and  some  of  the  bituminous  products  of  the 
decomposition  distilling  into  the  earthy  strata  next  to  the 
coal  have  formed  with  it  the  shales  which  differ  from  coal 
in  that  the  fixed  residue  left  on  their  distillation  consists 
of  earthy  matter  instead  of  coke.  It  is  also  perfectly  well 
known  that  in  some  of  the  more  extensive  peat  bogs  a 
trickle  of  oil  is  occasionally  found  escaping  from  the  de- 
composing mass,  showing  that  even  in  the  early  stages  of 
the  action,  oils  are  produced,  while  it  was  from  a  spring 
of  oil  in  the  shale  measures  of  the  Alfreton  Colliery  that 
Young  first  got  the  idea  of  utilizing  shale  for  distillation 
as  a  source  of  mineral  oil. 

It  has  been  known  for  centuries  that  in  certain  districts 
of  America  and  Eastern  Europe  a  scum  of  oil  would  fre- 
quently gather  on  the  surface  of  the  pools  and  streams, 
and  these  districts  have  since  become  famous  as  the  great 
sources  of  American  and  Russian  oil  supply.  Although 
many  observers  cling  to  the  belief  that  the  oil  fields  have 
been  formed  by  animal  or  mineral  agency,  there  seems  but 
little  reason  to  doubt  that  our  liquid  fuels,  like  the  solid, 
are  of  vegetable  origin,  and  are  indeed  by-products  of  great 
subterranean  distillations,  in  which  at  high  pressures  and 
comparatively  low  temperatures  the  accumulated  vegeta- 
tion of  past  ages  has  been  partly  liquefied  or  even  gasified, 
as  the  same  areas  which  yield  our  stores  of  mineral  oil  are 
also  famed  for  the  production  of  natural  gas. 

The  Pennsylvania  oil  fields  of  America  yield  crude  oil 
consisting  largely  of  members  of  that  group  of  hydrocar- 
bons which  we  know  as  the  "saturated  series,"  the  lower 
and  more  simple  members  of  which  are  gases,  and  with  the 
fifth  member  commence  to  give  highly  volatile  liquids 
yielding  the  pentane  which  we  use  for  our  standard  of 


PLANT'S  GROWTH  AND  DECAY  113 

light,  and  the  hexane  and  heptane  known  as  "petrol"  in 
England  and  "gasoline"  in  America,  while  higher  members 
of  the  series  constitute  the  burning,  lubricating,  and  fuel 
oils  which  have  played  so  important  a  part  in  the  technical 
world  during  the  past  fifty  years. 

The  Russian  oils,  on  the  other  hand,  contain  hydrocar- 
bons of  a  slightly  different  character,  having  as  chief  con- 
stituents "naphthenes,"  a  group  which,  although  in  many 
properties  similar  to  the  saturated  hydrocarbons,  yet  in 
composition  must  be  ranked  with  the  unsaturated.  So 
laborious,  however,  is  the  separation  of  the  hydrocarbons 
present  in  these  great  natural  distillates,  that  our  knowl- 
edge of  their  constituents  is  still  far  from  perfect,  and 
recent  researches  upon  the  tars  obtained  at  low  tempera- 
tures from  coal  show  that  they  are  characterized  also  by 
the  presence  of  the  naphthene  group. 

The  valleys  of  the  Alleghany,  which  gave  so  abundant 
a  supply  of  oil  to  Drake  and  the  pioneers  of  the  oil  industry 
in  the  early  sixties,  also  yielded  that  great  output  of 
natural  gas  which  concentrated  the  manufacturing  activity 
of  America  to  so  large  an  extent  in  these  districts.  Al- 
though such  gas  is  found  in  small  quantities  in  many  parts 
of  the  world,  no  output  of  the  same  magnitude  has  ever 
been  discovered. 

This  gas,  which  is  by  far  the  most  valuable  of  the  gas- 
eous fuels,  is  practically  methane. 

Weight  for  weight  natural  gas  is  the  most  valuable  of 
all  the  fuels,  having  a  calorific  value  of  12,008  calories 
(21,615  British  thermal  units),  and  its  history  affords  a 
graphic  object  lesson  of  what  within  a  hundred  years  will 
be  our  condition  with  regard  to  coal  supply,  the  actions, 
however,  having  been  concentrated  into  a  period  of  not  less 
than  fifty  years. 

With  the  first  discovery  of  natural  gas  waste  of  the  gross- 
est character  took  place,  followed  by  a  period  in  which, 
the  value  of  the  gas  having  been  realized,  it  was  con- 
sumed with  the  utmost  prodigality,  and  no  thought  was 
8 


114  MODERN  SCIENCE  READER 

ever  given  to  the  future.  Then  as  reduced  pressures  in 
the  supply  began  to  give  a  warning  note,  economy  at  length 
began  to  be  exercised,  while  now  the  rapidly  decreasing 
supply  threatens  failure  at  an  early  period  and  has  at 
length  forced  attention  to  every  point  at  which  economy 
can  be  obtained. 


COAL:  ITS  COMPOSITION  AND 
COMBUSTION1 

GENERAL   DISCUSSION   OF   THE   ELEMENTS   THAT  PROMOTE 
COMBUSTION 

BY  WILLIAM  H.  BOOTH 

IT  is  usual  to  speak  of  heat  under  various  names.  It  is 
thermometric,  specific,  or  latent.  By  the  first  is  meant 
that  property  of  heat  which  sets  up  molecular  vibrations 
in  a  substance,  which  are  capable  of  transmission  to  sur- 
rounding bodies  by  radiation  or  by  contact. 

By  specific  heat  we  mean  the  amount  of  heat  energy  that 
is  necessary  to  set  up  a  certain  degree  of  thermometric  heat 
in  a  unit  of  mass  of  some  body.  The  same  addition  of  heat 
to  a  pound  of  lead  that  has  made  a  pound  of  water  com- 
fortably warm  would  enable  the  lead  to  burn  a  hole 
through  a  man's  hand. 

By  latent  heat  is  understood  heat  that  has  become  con- 
verted into  energy  of  condition  without  thermometric 
manifestation,  as  when  heat  added  to  ice  at  thirty-two0  F. 
enables  that  ice  to  exist  as  a  free  liquid  and  still  only  to 
affect  the  thermometer  to  thirty-two0  F.  Here,  heat  repre- 
sents mobility  of  the  molecules. 

In  a  wide  general  sense  every  chemical  reaction  may  be 
cited  as  a  combustion.  Certainly  the  converse  is  true— 
combustion  is  a  chemical  reaction.  All  substances  are,  in 
a  broad  sense,  fuels.  Many  are  difficult  to  ignite.  Many 
have  already  entered  into  combustion  or  are  results  of 
chemical  processes  so  energetic  that  it  is  difficult  to  estab- 
lish any  other  reaction.  Lime,  for  example,  is  the  product 

'Abstract  of  paper  read  before  the  Association  of  Engineers-in- 
Charge  (England).  From  Scientific  American  Supplement  No.  1729, 
February,  1909. 

115 


116  MODERN  SCIENCE  READER 

of  a  combination  of  the  metal  calcium  with  the  gas  oxygen, 
and  the  energy  of  union  is  so  great  that  the  metal  calcium, 
though  one  of  the  most  common  of  nature's  so-called  ele- 
ments, is  hardly  known  in  nature  except  as  an  oxide  or  a 
carbonate. 

Aluminium  is  a  metal  that  unites  so  firmly  with  oxygen 
that  it  will  usurp  the  place  of  iron  in  a  mass  of  burned 
iron,  and  convert  a  mass  of  mill  scale  into  pure  iron  by 
itself  becoming  an  oxide.  Hence  the  thermic  process.  The 
fuels  that  are  commonly  regarded  as  fuels  are  wood  and 
coal  and  mineral  oils.  These  are  found  free  in  nature,  and 
are  easily  burned  and  give  out  considerable  heat.  Ages  of 
experience  have  taught  us  that  air  is  necessary  to  combus- 
tion. The  fire  of  wood  burns  the  better  when  the  wind 
blows  upon  it.  The  wind  we  can  feel,  if  we  cannot  see  it. 
The  effect  is  to  blow  away  the  C02  and  leave  the  fuel  freely 
exposed  to  fresh  supplies  of  oxygen. 

Carbon  gas  is  ideal  only.  Carbon  exists,  as  gas,  in  the 
electric  arc  at  3,600°  C.  When  carbon  is  burned  to 
monoxide,  CO,  there  are  set  free  4,415  B.t.u.  per  pound. 
When  this  monoxide  is  burned  to  dioxide  a  further  heat  of 
10,232  B.t.u.  is  set  free.  Why  the  difference  ?  Physicists 
say  that  the  first  oxidation  also  generates  at  least  10,232 
B.t.u.  or  5,817  units  more  than  is  thermometrically  discov- 
erable. They  say  that  the  5,817  units  have  become  latent 
because  the  carbon  which  was  solid  is  now  gaseous  in  the 
CO.  Therefore,  the  total  heat  of  combustion  of  carbon 
gas,  if  carbon  could  be  taken  in  its  gaseous  form,  is  10,232 
X  2=20,464  B.t.u.  per  pound. 

Now,  in  CO2  there  are  12  parts  of  C.  and  32  parts  of  0,  or 
C  :  0  :  :  3  :  8. 

Then  20,4  64  X%= 7, 674 

B.t.u.  produced  by  the  combustion  of  one  pound  of  oxygen. 

Now,  for  combustion  with  hydrogen :  One  pound  of  this 
gas  gives  62,100  B.t.u.  The  ratio  of  the  two  elements 
H20  is  1  :  8. 

Now,  62,100xys=7J63 


COAL:  ITS  COMPOSITION  117 

B.t.u.  This  is  almost  exactly  the  heat  developed  when 
oxygen  is  destroyed  by  gaseous  carbon. 

In  each  case  three  volumes  of  gas  become  two  volumes, 
so  there  is  no  difference  due  to  a  different  degree  of  con- 
densation. Let  there  be  next  taken  the  heat  of  combustion 
of  a  series  of  hydrocarbons:  C2H2,  C2H4,  CH4,  C2H6  and 
C6H6.  These  are  shown  in  the  second  column  in  B.t.u.  per 
pound  of  the  hydrocarbon. 

B.t.u.  B.t.u. 

C2H0  =  21,850  X  26/80  =  7,003 
C2H4  =  21,927  X  28/96  =  6,395 
CH4  =  24,017  X  16/64  =  6,003 
C2H6  =  22,338  X  30/112  =  5,983 
C6H6  =  18,094  X  78/240  =  5,880 

for  benzine  vapor. 
C6H6  =  17,930  X  78/240  =  5,827 

for  benzine  liquid. 

In  the  third  column  is  the  ratio  of  the  oxygen  consumed, 
and  in  the  fourth  the  heat  units  per  pound  of  oxygen  used. 
This  table  gives  room  for  thought.  It  shows,  in  the  first 
place,  a  gradually  decreasing  result  in  heat  set  free  per 
pound  of  oxygen  destroyed.  Between  C2H2  and  C6H6  two 
hydrocarbons,  with  exactly  the  same  proportions  of  carbon 
and  hydrogen,  using  up  exactly  the  same  weight  of  oxygen 
per  pound  of  each,  there  is  a  difference  of  heat  set  free  of 
seventeen  per  cent,  (nearly).  Burned  as  vapor  and  burned 
as  liquid,  benzine,  C6H6,  gives  a  different  amount  of  heat 
again.  The  figures  become  confusing  when  thus  treated, 
and  it  is  necessary  to  deal  with  them  by  the  molecule,  as 
they  are  treated  by  the  chemist. 

How  coal  is  formed  cannot  be  said  with  absolute  cer- 
tainty, but  the  probability  is  that  the  coal  plants  accumu- 
lated like  the  accumulation  of  the  peat  bogs  and  became 
buried  in  sand  and  gradually  sank  to  a  considerable  depth 
in  the  earth.  There  under  the  influence  of  heat  and  pres- 
sure, the  vegetable  matter  changed  its  nature.  Its  watery 
constituents  were  driven  off  and  the  remaining  portions 


118  MODERN  SCIENCE  READER 

carbonized,  and  then  were  also  set  up  those  reactions  that 
produced  what  we  term  the  bituminous  quality.  There  is 
no  bitumen  in  coal,  but  what  we  mean  by  bituminous  is 
known  to  all.  Some  coal  was  so  much  heated  that  its 
hydrocarbonaceous  matter  was  driven  off  to  be  absorbed  in 
other  rocks,  such  as  certain  clay  shales,  or  it  escaped  to  the 
surface  and  was  lost.  Thus  possibly  the  Welsh  coal  was 
formed  with  its  short  flaming  qualities  that  earn  for  it  the 
term  "smokeless,"  because,  though  not  smokeless  in  all  cir- 
cumstances, it  can  be  burned  without  smoke  if  any  simple 
precautions  are  taken.  Exposed  to  still  greater  heat  or 
pressure  or  both  almost  all  the  hydrogenous  matter  is 
driven  off  and  the  coal  is  converted  into  anthracite,  a  flinty 
hard  variety  of  carbon. 

If  samples  of  coal  be  examined  their  composition  cannot 
be  regarded  as  so  different  as  is  their  behavior.  There  is 
a  substance  found  in  parts  of  the  West  Indies  which  re- 
sembles anthracite  in  appearance,  but  it  is  plastic  brittle. 
It  is  said  not  to  contain  more  than  one  per  cent,  of  hydro- 
gen to  ninety-nine  of  carbon.  Yet  this  one  per  cent, 
entirely  changes  the  nature  of  the  carbon,  producing  a 
smoky  fuel  and  the  capacity  of  becoming  soft  with  but  a 
moderate  heat.  Ordinary  bituminous  coal  contains  very 
much  more  hydrogen  but  does  not  soften  at  the  same  low 
temperature,  and  when  it  is  exposed  to  heat  it  softens  in 
spots  and  gives  off  tar  vapors.  Nothing  is  known  really  of 
the  chemical  composition  of  coal.  It  can  be  found  out  easily 
and  with  close  accuracy  just  how  much  hydrogen,  how 
much  carbon,  oxygen  or  sulphur  a  piece  of  coal  does  con- 
tain, but  how  the  atoms  of  these  elements  are  joined  to- 
gether seems  quite  beyond  finding  out  at  the  present  time. 
Thus,  if  a  piece  of  coal  be  exposed  to  distillation  in  a  retort 
and  the  different  things  collected  that  are  produced,  there 
will  be  found  tar,  creosote,  carbolic  acid,  cresylic  acid, 
hydrogen,  various  light  and  heavy  hydrocarbon  gases,  and 
so  much  water  and  ammonia.  But  it  cannot  be  said  these 
substances  are  present  in  the  coal.  They  have  simply  been 


COAL:  ITS  COMPOSITION  119 

built  up  or  broken  down  from  the  material  of  which,  coal 
is  really  formed,  and,  for  anything  known  to  the  contrary, 
a  piece  of  bituminous  coal  is  homogeneous  throughout  in 
chemical  composition  and  only  splits  up  into  many  and 
various  bodies  when  heated.  It  may  be  inferred  that  if 
the  coal  begins  to  split  up  as  soon  as  heated  so  it  will  con- 
tinue to  split  up  as  more  heat  is  applied,  the  material  split- 
ting up  more  and  more  into  lighter  and  heavier  portions 
so  that  nothing  but  pitch  remains  in  the  still,  and  after  a 
little  further  heating,  even  this  is  resolved  into  coke  and 
vapor. 

When  coal  is  burned  in  a  fire  exposed  to  air,  there  is  a 
perhaps  more  complicated  set  of  reactions  put  into  oper- 
ation. These  are  operations  both  of  distillation  and  com- 
bustion. An  experiment  first  shown  by  Horace  Allen  was 
the  sprinkling  upon  a  red-hot  plate  of  porcelain  of  some 
finely  divided  bituminous  coal.  At  once  vapor  commences 
to  be  given  off  and  a  dark  spot  surrounds  each  bit  of  coal. 
The  coal  does  not  glow  so  long  as  the  vapor  is  coming  away 
from  it.  When  the  vapor  ceases  to  escape  the  coal  begins 
to  get  hot  and  the  dark  spots  on  the  plate  disappear.  The 
coal  now  begins  to  glow,  to  sparkle ;  in  fact,  to  oxidize  and 
disappear. 

Now,  from  this  experiment  much  may  be  learned.  First, 
that  the  primary  effect  of  heating  coal  is  to  drive  off  its 
volatile  portions.  Actually,  of  course,  heat  renders  the 
coal  partly  volatile  and  drives  this  part  away.  The  vapor- 
izing of  this  demands  heat  and  the  vapor  renders  so  much 
heat  latent  that  it  dulls  the  surface  of  the  plate.  When 
this  chilling  effect  is  finished  by  the  escape  of  all  vapor, 
the  remaining  bit  of  coke  gradually  becomes  hotter.  But 
it  does  not  oxidize  brightly  until  it  has  attained  a  high 
temperature.  These  actions  teach  that  coal  upon  a  grate 
will  be  very  seriously  cooled  if  fresh  coal  is  thrown  upon 
it,  and  that  the  volatile  matter  must  be  thrown  off  any 
piece  of  coal  before  its  carbon  skeleton  will  begin  to  burn. 
In  a  thick  bed  of  coked  coal  on  a  grate  the  chilling  effect 


120  MODERN  SCIENCE  READER 

of  fresh  coal  may  not  extend  right  down  to  the  grate  sur- 
face and  the  fuel  next  the  grate  will  burn  with  the  incom- 
ing air  at  the  same  time  as  the  gas  from  the  green  coal 
burns  on  the  surface.  If  the  fuel  bed  is  thin,  the  carbon 
dioxide  first  produced  on  the  grate  comes  to  the  surface  as 
dioxide,  and  hinders  the  combustion  of  the  volatile  matter. 
If  the  fuel  be  thick  the  dioxide  may  be  converted  into 
monoxide  in  its  upward  passage  through  the  fuel,  and  this 
will  again  hinder  the  combustion  of  the  volatiles.  The 
final  gaseous  mixture  above  the  fuel  will  be  very  complex, 
and  usually  it  will  be  by  no  means  very  hot.  Experience 
tells,  as  explained  by  Mr.  Swinburne,  that  this  mixed  mass 
ought  to  be  kept  hot  in  a  non-absorbent  furnace  until 
combustion  is  complete. 

What  now  deserves  attention  is  a  simple  means  of 
examination  of  a  fire  with  the  object  of  ascertaining  to 
what  degree  combustion  has  attained.  This  is  blue  glass 
of  a  deep  tint.  Blue  glass  will  not  permit  the  passage  of 
light  of  a  wave  length  greater  than  blue.  It  is  because  it 
will  not  permit  this  that  it  is  blue.  High-temperature 
radiation  has  the  shortest  wave  length.  Violet  light  has 
double  the  number  of  waves  per  inch  that  represent  red 
light,  and  red  light  has  millions  of  times  the  waves  per  inch 
as  sound  notes.  Sound  would  become  visible  to  a  man  mov- 
ing fast  enough  toward  its  vibratory  origin.  Low-tempera- 
ture flame  is  red,  orange,  yellow;  blue  is  hot;  violet  is  so 
potent  that  it  brings  about  various  chemical  reactions,  as  in 
photography.  A  red-hot  brick  seen  through  blue  glass  be- 
comes drab,  and  gives  no  illumination.  A  brilliantly  incan- 
descent brick  lined  furnace  seen  through  blue  glass  appears 
of  a  light  French  gray,  and  is  of  illuminating  quality. 

Now,  if  a  dull  flaming  fire  be  observed,  such  as  is 
obtained  if  badly  mixed  gases  rise  directly  upward  from 
the  fire  to  pass  among  cold  tubes,  there  will  be  seen  through 
blue  glass  no  illumination  above  the  fire  beyond  about  six 
inches.  The  flames  are  resolved  into  dark  streams  of  gas; 
no  light  comes  from  them.  But  if  the  interior  of  a  furnace 


COAL:  ITS  COMPOSITION  121 

be  observed  when  properly  lined  with  brick,  and  with 
suitable  direction  of  flow  and  air  mixture,  the  whole  will 
be  illuminated.  Streaks  and  splashes  of  dark  gas  will  be 
seen  coming  forward  over  the  fire,  and  these  melt  away  as 
they  travel,  and  burn  and  help  to  keep  up  the  temperature. 
The  dark  streaks  are  simply  gas  not  hot  enough  to  give 
violet  light.  They  are  red  or  yellow  flames  of  burning  gas 
ready  to  produce  smoke  if  sent  upon  cold  surfaces.  Kept 
off  cold  boiler  plates,  they  complete  their  high  temperature 
combinations,  and  may  then  be  used  for  heating  anything. 

It  is  not  that  blue  glass  marks  the  state  of  combustion 
beyond  which  one  must  pass,  but  it  seems  certain  that  if  a 
properly  mixed  gas  attains  this  temperature  before  ex- 
posure to  cold  surfaces,  it  will  be  properly  burned.  It 
would  be  interesting  to  experiment  with  red,  yellow,  and 
green  glass,  so  as  to  find  how  these  help  in  analyzing  the 
state  of  a  fire.  It  is  certain  that  if  blue  glass  cuts  the 
flame  very  short  there  is  imperfect  combustion. 

Now  I  have  not  told  you  much  about  coal,  for  I  know 
nothing  myself  of  the  way  it  is  put  together.  All  I  can 
infer  is  that  a  very  small  amount  of  combined  hydrogen 
will  change  the  physical  nature  of  much  carbon.  Analysis 
of  coal  seems  to  point  to  the  presence  of  oxygen  as  the 
potent  cause  of  so-called  bituminosity.  Knowledge  of  the 
phenomena  of  heat— such  as  latency— teaches  that  the  fuel 
bed  must  be  chilled  when  fresh  coal  is  giving  off  vapor. 

On  the  supposed  atomic  arrangement  of  hydrocarbon, 
speculation  may  be  indulged  in  on  the  facts  that  hydro- 
carbon is  first  attacked  by  the  oxygen,  and  that  the  carbon 
is  set  free  by  itself  or  in  some  different  combination  with 
hydrogen,  and  so  readily  condenses  on  the  first  cold  surface. 
And  so  it  is  learned  to  mix  atoms  of  oxygen  in  excess  of 
what  the  hydrogen  atoms  will  snatch  up  and  to  maintain 
everything  hot  until  the  carbon  has  had  its  chance  to  find 
its  own  atoms  of  oxygen.  And  as  it  may  be  inferred  that 
a  thick  fuel  bed  implies  shortness  of  oxygen  above  the 
fire— for  the  fire  has  perhaps  been  converted  into  a  gas 


122  MODERN  SCIENCE  READER 

producer— so  it  may  be  learned  not  always  to  regulate 
combustion  at  the  chimney  damper,  but  to  keep  this  open 
sufficiently  to  pull  in  all  the  air  we  need  as  a  maximum 
above  the  fire,  and  to  regulate  the  combustion  by  combined 
movements  of  the  door  grids  and  ashpit  dampers. 

Safety  valves  are  locked  up  from  tampering;  why  not 
also  lock  the  chimney  damper  ?  It  should  be  locked,  for  it 
is  not  fit  to  be  used  as  a  regulator  of  the  combustion  of 
bituminous  coal,  for  this  is  a  double  process,  the  coal  burn- 
ing partially  as  solid  fuel  on  the  grate  and  partly  as  gas 
above  the  fire,  and  each  operation  requires  separate  and 
yet  conjoint  air  regulation. 

Ordinary  coal  has  a  calorific  capacity  of  about  14,000 
B.t.u.  per  pound.  The  volatile  matters  distilled  from  it 
have  a  capacity  of  18,000  to  24,000  B.t.u.  The  extra  4,000 
to  10,000  heat  units  they  now  possess  are  borrowed  from 
the  heat  of  combustion  of  the  solid  fuel  on  the  grate,  and 
when  the  green  gas  is  wasted  unburned  it  is  carrying  with 
it  the  latent  heat  of  distillation.  Assuming  20,000  as  its 
average  heat  value  and  assuming  one  third  of  the  coal  to  be 
volatile,  the  green  gases  carry  off  nearly  half  the  heat  value 
of  the  coal. 

Though  the  molecular  structure  of  coal  may  not  be  dis- 
coverable, there  can  be  no  doubt  as  to  the  results  of  the 
systems  of  combination  ordinarily  adopted.  If  fired  on  the 
coking  system,  the  gas  is  driven  off  more  or  less  steadily  and 
continuously,  and  places  less  of  a  tax  on  the  surface  at  any 
one  moment  in  respect  of  maximum  air  supply  above  the 
fuel  to  burn  the  gas  than  is  levied  when  fresh  coal  is  spread 
heavily  over  a  fire  at  more  or  less  wide  intervals  of  time. 

In  solid  fuel  the  carbon  has  not  changed  its  state,  but 
any  hydrogen  has  been  somehow  rendered  solid  by  its 
combination  with  carbon. 

The  gaseous  hydrocarbons  become  liquids  when  their 
molecular  weight  gets  up  to  about  seventy  to  eighty,  and 
solids  begin  to  appear  when  the  molecular  weight  reaches 
128  or  136. 


COAL:  ITS  COMPOSITION  123 

The  trouble  with  coal  is  that  it  is  not  simply  a  hydrocar- 
bon of  even  unknown  proportion,  or  a  mixture  of  hydro- 
carbons. It  contains  oxygen  built  into  its  solid  structure, 
and  this  oxygen  is  not  necessarily  there  as  water  with  some 
of  the  hydrogen  as  H20.  But  it  is  there,  and  it  comes  off 
in  distillation,  and  forms  that  complex  substance— tar. 
Tar  contains  phenols— carbolic  acid,  C6H5OH,  is  one  of 
them — and  there  are  phenols  with  eight  and  nine  carbon 
atoms,  and  even  ten. 

It  would  fill  this  whole  paper  only  to  name  the  known 
carbon  or  organic  compounds  containing  the  three  elements 
C,  H  and  0  variously  hooked  together.  But  with  all  the 
knowledge  of  the  many  substances  given  out  from  tar,  it 
cannot  be  said  they  are  present  in  coal  in  the  form  they 
take  on.  But  the  main  facts  of  physics  can  be  relied  on. 
Heat  is  swallowed  up  when  solids  are  liquefied  or  liquids 
gasified,  and  these  are  the  things  that  happen  to  coal  when 
burned.  They  retard  its  perfect  combustion,  and  the 
engineer  who  can  best  fit  practice  to  meet  nature's  laws  on 
proper  conditions  will  best  utilize  coal  as  regards  economy 
and  cleanliness.  The  knowledge  of  what  happens  thermo- 
chemically  in  the  life  history  of  the  hydrocarbons  furnishes 
ample  explanation  of  the  failure  of  ordinary  methods  of 
burning  it  without  heat  or  temperature  conservation.  The 
behavior  and  properties  of  the  gaseous  hydrocarbons  may 
be  regarded  as  the  gaps  in  the  bounding  walls  of  knowledge 
through  which  glimpses  may  be  had  sufficient  to  serve  as 
the  jumping-off  points  of  the  flying  machines  of  specu- 
lative imagination ;  and  after  all  it  is  imagination  which 
differentiates  the  engineer  from  the  mere  mechanic. 
Armies  are  never  likely  to  be  conveyed  by  either  balloon 
or  flying  machine,  but  both  these  frail  craft  may  serve  to 
point  the  way  by  which  an  army  may  best  proceed.  The 
mere  speculative  engineer  will  not  perhaps  carry  out  work 
so  well  as  the  constructional  man  who  follows  beaten  paths, 
but  his  speculative  habit  of  mind  does  enable  him  to  point 
the  way  for  others  to  follow. 


THE  COAL-TAR  DYE  INDUSTRY1 

ITS    WONDERFUL    RISE    AND    ITS    IMPORTANCE 

THE  semi-centennial  celebration,  in  1906,  of  Perkin's 
discovery  of  the  first  of  the  aniline  or  coal-tar  dyes  passed 
almost  unnoticed  by  the  general  public,  and  the  term 
"coal-tar  dyes"  conveys  very  little  meaning  to  the  majority 
of  people.  Yet  these  dyes  are  applied  to  a  great  many 
objects  that  everybody  sees  and  uses  daily— fabrics  and 
fibers  of  every  kind  used  in  the  manufacture  of  clothing, 
ribbons,  curtains,  carpets,  etc.,  matting,  straw  and  felt 
hats,  leather  goods,  and  many  other  articles.  Of  all  the 
great  chemical  establishments  of  Germany  the  largest  are 
those  which  are  devoted  to  the  preparation  of  these  dyes. 
One  of  these  factories  has  a  capital  of  $8,000,000  and  a 
force  of  more  than  6,000  workers,  including  200  chemists. 

The  art  of  dyeing  is  3,000  years  old,  but  the  ancient 
dyers  had  only  a  few  colors :  madder,  saffron,  and  possibly 
orchil  for  red,  indigo  for  blue,  and  saffron  for  yellow,  in 
addition  to  the  celebrated  Tyrian  purple.  The  last  named 
was  the  secretion  of  a  shell  fish,  the  others  were  derived 
from  plants,  and  all  were  furnished  directly  by  nature. 

The  discovery  of  America  brought  new  natural  dyes- 
cochineal,  logwood.  Brazilwood,  quercitron,  and  others— 
and  the  opening  of  the  sea  route  to  India  made  indigo  less 
costly  and  also  stimulated  the  cultivation  of  woad,  a 
European  plant  furnishing  a  dye  very  like  indigo.  The 
dyes  named  above,  with  a  few  of  mineral  origin,  consti- 
tuted, down  to  the  beginning  of  the  nineteenth  century,  the 
entire  resources  of  the  dyer,  with  which  he  colored  yarns 
by  complicated  processes  and  often  with  uncertain  results. 

Published  in  Eosmos;  translation  published  in  Scientific  American 
Supplement,  June  12,  1909 

124 


THE  COAL-TAR  DYE  INDUSTRY 


125 


126  MODERN  SCIENCE  READER 

One  of  the  first  achievements  of  the  nineteenth  century, 
in  the  field  of  chemical  technology,  was  the  production  of 
illuminating  gas  from  coal.  The  dry  distillation  of 
bituminous  coal  yielded,  in  addition  to  gas,  various  tarry 
matters  which  were  collectively  named  gas  tar,  or  coal  tar. 
This  at  first  was  a  perfectly  useless  and  annoying  waste 
product. 

In  1834  Runge  obtained  from  coal  tar,  by  distillation,  a 
liquid  of  basic  properties  which  he  called  cyanol.  Before 
this,  in  1826,  Unverdorben  had  obtained  by  the  dry  distil- 
lation of  indigo  a  basic  liquid  which  he  called  crystalliri, 
because  it  formed,  wTith  acids,  crystallizable  salts,  and 
about  the  same  time  Zinin  had  obtained  a  basic  liquid, 
which  he  called  benzidam,  by  treating  nitrobenzol  with 
ammonium  sulphate.  Hofmann  proved  the  identity  of 
these  three  liquids.  The  substance  is  now  called  aniline, 
from  anil,  the  Arabic  name  of  indigo,  and  from  it  many  of 
the  coal-tar  colors  have  been  derived.  The  discoveries  of 
Hofmann  and  Zinin  made  it  possible  to  obtain  aniline  in 
large  quantities.  Coal  tar  contains  aniline,  but  too  little 
to  pay  for  extracting.  On  the  other  hand,  coal  tar  contains 
a  large  amount  of  benzol,  which  can  easily  be  separated. 
By  treatment  with  nitric  acid,  benzol  can  be  converted  into 
nitrobenzol,  and  from  this  aniline  can  be  obtained  by 
Zinin 's  process. 

In  1856  William  Henry  Perkin,  who  was  attending  Hof- 
mann's  lectures  at  the  Royal  College  of  Chemistry  in 
London,  attempted  to  produce  quinine  by  oxidizing  aniline 
with  potassium  bichromate,  and  obtained  a  black  precipi- 
tate. Others  had  done  the  same  and  gone  no  further,  but 
Perkin  found  that  the  precipitate  dissolved  in  alcohol, 
forming  a  violet  solution,  with  which  silk  could  be  dyed. 
In  the  following  year  he  started  a  factory  for  the 
production  of  the  new  dye,  which  was  first  called  * '  Tyrian 
purple,"  and  subsequently  became  known  as  mauve,  aniline 
violet,  or  Perkin 's  violet.  Aniline  red,  or  fuchsine,  was 
discovered  also  in  1856,  by  Nathanson,  but  its  commercial 


THE  COAL-TAR  DYE  INDUSTRY  127 

production  was  first  accomplished  in  France  by  Berguin. 

The  price  of  aniline,  at  first  nearly  three  dollars  per 
pound,  was  soon  lowered  by  competition.  It  was  treated 
with  all  sorts  of  reagents  in  the  hope  of  producing  new 
dyes.  A  mixture  of  aniline  and  fuchsine  yielded  aniline 
blue,  and  with  the  production  of  the  first  aniline  yellow, 
called  chrysaniline  or  phosphine,  a  feeble  competition  with 
vegetable  dyes  began. 

Practice  outran  theory  and  produced  dyes  of  which  the 
chemical  character  and  relations  were  little  known.  Again 
it  was  Hofmann  who  illuminated  the  darkness.  He  deter- 
mined the  chemical  nature  of  fuchsine  and  discovered  iodine 
violet  and  iodine  green,  which  were  at  once  manufactured 
and  put  on  the  market.  They  were  made  under  pressure, 
often  in  old  champagne  bottles,  which  had  a  disagree- 
able habit  of  exploding,  but  possessed  the  advantage  of 
cheapness. 

These  two  new  dyes  were  discovered,  or  rather  invented, 
in  accordance  with  scientific  principles,  and  they  proved 
that  the  chemistry  of  the  coal-tar  colors  was  being  developed 
correctly.  TLis  development  was  further  promoted  by 
Kekule's  ingenious  theory  of  the  structure  of  the  aromatic 
hydrocarbons  which  solved  the  intricate  problems  of  isom- 
erism. 

Kekule's  pupil,  Bayer,  was  one  of  the  first  to  apply  this 
theory  to  the  coal-tar  colors,  and  after  seventeen  years' 
labor  he  achieved  one  of  the  greatest  triumphs  of  chem- 
istry, the  synthesis  of  indigo. 

Meanwhile  Graebe  and  Liebermann  had  taken  up  the 
study  of  anthracene,  also  a  constituent  of  coal  tar.  After 
proving  that  anthracene  can  be  obtained  from  alizarine, 
the  red  coloring  matter  of  the  madder  root,  they  endeavored 
to  reverse  the  process,  and  make  alizarine  from  anthracene. 
They  succeeded,  and  so  did  Perkin,  in  the  same  year,  1869. 
The  German  chemists  applied  for  an  English  patent  one 
day  earlier  than  their  English  rival,  and  so  the  English 
market  was  secured  for  German  artificial  alizarine.  Now 


128  MODERN  SCIENCE  READER 

began  the  first  serious  competition  between  a  natural  and 
an  artificial  dyestuff.  The  latter  won,  for  a  root  yielding 
one  or  two  per  cent,  impure  coloring  matter  and  requiring 
valuable  land  for  its  cultivation  could  not  long  compete 
with  factories  producing  the  pure  dyestuff  from  coal  tar. 

In  dyeing  with  most  of  the  colors  so  far  mentioned  the 
yarn  must  first  be  impregnated  with  a  substance,  called  a 
mordant,  which  has  the  power  to  fix  the  color.  Different 
dyes  require  different  mordants.  Dyes  which  are  fixed  by 
compounds  of  alumina  or  chromium  are  called,  simply, 
mordant  dyes.  Tannin  dyes  are  those  which  require  the 
application  of  tannin  as  a  mordant.  After  a  time  the 
chemists  succeeded  in  producing  dyes  which  color  wool  and 
silk  without  the  use  of  any  mordant.  As  these  dyes  were 
obtained  by  treating  tannin  dyes  with  sulphuric  acid,  and 
are  used  in  a  slightly  acid  solution,  they  are  called  acid 
dyes.  In  this  class  belong  the  azo  dyes,  the  manufacture 
of  which,  commenced  about  1875,  has  developed  amazingly. 
They  are  now  the  most  important  of  all  dyes  and  have  been 
the  most  formidable  competitors  of  cochineal  and  dyewoods. 

In  1884  appeared  the  first  direct  cotton  dye;  that  is,  a 
dye  which  colors  vegetable  as  well  as  animal  fibers,  without 
mordanting.  Many  such  dyes  were  soon  produced  and 
were  eagerly  adopted  by  dyers,  as  they  saved  both  time 
and  money.  They  were  not  as  fast  as  the  mordant  dyes, 
but  this  defect  was  remedied  toward  the  end  of  the  century 
by  the  production  of  the  sulphur  dyes,  which  also  require 
no  mordant  on  either  vegetable  or  animal  fibers  and  yet 
leave  little  to  be  desired  in  point  of  permanence. 

Some  of  the  direct  cotton  dyes  can  be  changed  in  color, 
after  application,  by  treating  the  dyed  goods  with  certain 
reagents.  Thus  blue  can  be  changed  to  black,  and  yellow 
to  bright  red,  and  the  new  colors  are  more  permanent  than 
the  originals.  This  suggested  the  production  of  colors 
within  the  fibers,  by  the  reaction  of  two  colorless  substances. 
Many  shades  are  now  produced  in  this  way.  They  are 
called  ice  colors  because  the  goods  are  usually  cooled  with 


THE  COAL-TAR  DYE  INDUSTRY  129 

ice  during  the  operation.  The  process  is  cheap,  as  the 
expense  of  heating  the  vats  with  steam,  which  is  necessary 
with  most  other  dyes,  is  saved.  It  is  also  very  rapid  and 
the  colors  are  very  permanent. 

Quite  recently  Professor  Friedlander  of  Vienna  has  pro- 
duced an  indigo  red,  which  contains  sulphur  and  is  there- 
fore called  thio-indigo.  In  its  permanence,  which  greatly 
surpasses  that  of  indigo  blue,  as  well  as  in  its  shade,  the 
new  dye  resembles  the  celebrated  Tyrian  purple  of 
antiquity. 

Now  let  us  glance  at  the  magnitude  and  importance  of 
the  coal-tar  dye  industry.  The  first  benefit  it  brought  was 
the  utilization  of  coal  tar,  which  cheapened  the  production 
of  gas  and  made  it  possible  to  establish  gas  works  in  small 
towns.  The  second  benefit  was  the  scientific  development 
of  the  arts  of  dyeing  and  calico  printing  which  had  prev- 
iously been  conducted  empirically  and  handed  down  from 
father  to  son.  The  chemists  who  produced  the  new  dyes 
also  extended  their  field  of  application  and  invented  new 
methods  of  treating  cotton,  linen,  silk,  wool,  felt,  jute,  furs, 
leather,  paper,  feathers,  straw,  tinsel,  wood,  and  other 
materials.  The  consequence  was  a  greatly  improved 
market  for  dyed  and  printed  goods  of  all  sorts,  and  for 
textile  fabrics  in  general.  Improved  printing  machinery, 
capable  of  printing  from  six  to  twelve  colors,  instead  of 
two  or  three,  was  invented.  The  production  of  the  new 
dyes  in  very  large  quantities  involved  the  treatment  of 
immense  amounts  of  raw  material  and  necessitated  the 
invention  of  machinery  for  crushing,  disintegrating,  mix- 
ing, and  heating.  Some  of  the  materials  are  heated  in 
iron  or  steel  shells,  called  digesters  or  autoclaves,  strong 
enough  to  withstand  a  pressure  of  fifty  or  one  hundred 
atmospheres.  Centrifugal  machines  and  huge  filter  presses 
are  employed  to  separate  the  dyes  in  solid  form.  In  the 
manufacture  of  the  azo  dyes  large  quantities  of  ice  are 
used,  and  ice-making  machinery  is  included  in  the  plant. 
All  these  things  benefit  the  steel  producer,  the  machine 
9 


130  MODERN  SCIENCE  READER 

builder,  and  the  mechanical  engineer,  while  the  manufac- 
turing chemist  derives  benefit  from  the  demand  for  nitric, 
sulphuric,  and  hydrochloric  acids,  soda,  dextrine,  and  other 
substances  consumed  in  vast  quantities  in  the  manufac- 
ture and  application  of  dyes. 

In  Germany  the  development  of  the  coal-tar  dye  in- 
dustry has  brought  another  and  more  general  benefit,  for 
it  was  the  principal  cause  of  the  establishment  of  the 
imperial  patent  office,  in  1877. 

Allied  to  the  production  of  dyes  is  that  of  remedies, 
germicides,  explosives,  perfumes,  photographic  developers, 
and  many  other  valuable  substances  from  coal  tar.  This 
industry  has  attained  gigantic  proportions.  A  few  of  its 
most  valuable  and  extensively  used  products  are  carbolic 
and  salicylic  acids,  saccharin,  antipyrine,  and  other  febri- 
fuges, artificial  vanilla  and  artificial  musk. 

The  coal-tar  dye  industry  has  conferred  a  benefit  of 
incalculable  value  upon  bacteriology  and  upon  all  man- 
kind by  furnishing  dyes  which,  when  applied  to  micro- 
scopic preparations,  make  it  possible  to  distinguish  and 
recognize  the  germs  of  typhoid,  cholera,  tuberculosis,  and 
other  diseases. 

The  first  aniline  dye  was  produced  in  England,  but  the 
manufacture  of  the  coal-tar  colors  has  been  developed 
chiefly  in  Germany,  where  it  may  be  regarded  as  a  national 
industry. 


NATURAL  AND  ARTIFICIAL 
PERFUMES1 

BY  DB.  MAX  HEIM 

SCARCELY  any  natural  sensation  strikes  deeper  into 
man 's  elemental  being  than  the  perception  of  the  fragrance 
of  flowers,  and  from  primeval  times  and  in  all  lands  he 
has  cherished  the  art  of  conserving  their  too  fleeting  per- 
fume and  adding  its  grace  to  his  environment.  Starting 
in  Egypt  this  art  spread  to  the  sunny  land  of  Greece,  and 
from  there  reached  Italy,  where,  at  the  time  of  the  first 
emperors,  it  was  practised  to  such  an  immoderate  extent 
that  Vespasian,  that  wise  observer  of  men,  found  occasion 
for  the  saying:  ''Mulieres  bene  olent,  si  nihil  olent"— 
*  *  ^omerujsmejl^  good  when  they  smell  of  nothing. ' ' 

But,  like  many^other  "wisePmeh  ^Before^amTlrfter  him, 
Vespasian  was  not  in  accordance  with  general  opinion; 
and  from  the  Middle  Ages  until  the  present  time  perfumes 
have  enjoyed  constant  favor  with  the  fair  sex.  Although 
they  are  no  longer  employed  upon  the  individual  person 
in  such  extravagant  quantities  as  in  earlier  times,  their 
use  has  become  more  general,  and  their  manufacture  has 
become  an  important  industry  of  to-day. 

If  we  inquire  into  the  principles  of  the  production  of 
these  perfumes,  we  find  that  we  have  to-day,  in  many  re- 
spects, the  same  path  to  follow  which  was  trodden  ages 
ago.  Aside  from  the  use  of  fragrant  flowers,  leaves,  and 
especially  balsams  and  resins,  simply  dried,  as  perfuming 
agents— as  in  the  case  of  incense— the  process  was  soon 
reached  of  impregnating  with  the  fresh  flowers  of  fragrant 
plants  some  liquid  which  absorbed  and  kept  the  perfume. 

Published  in  Prometheus,  translation  in  Scientific  American  Sup- 
plement, September  17,  1904. 

131 


132  MODERN  SCIENCE  READER 

Certain  fats  and  oils  were  soon  recognized  as  the  best 
mediums  for  this,  and  such  were  specially  prepared— we 
might  almost  say  made  aseptic— by  the  Greek  physician 
Dioscorides,  under  Nero,  through  boiling  with  water,  salt 
and  wine.  If  freshly-dried  flowers  are  immersed  in  a  fat 
or  oil  thus  purified,  and  slightly  warm,  and  if  they  are 
replaced  after  a  few  hours  by  new  ones,  and  this  process 
repeated  several  times,  there  is  obtained  in  the  first  case 
a  product  resembling  a  salve  or  a  pomade,  and  in  the  second  ^ 
an  oil,  which  retains  the  perfume  of  the  flowers  in  greater 
or  less  degree,  according  to  the  quantity  employed,  but 
always  in  perfect  naturalness  and  purity. 

This  old  method,  with  some  improvements,  is  employed 
at  the  present  time  to  a  very  large  extent,  especially  in 
the  south  of  France,  in  the  neighborhood  of  Cannes,  Grasse 
and  Nice.  The  most  delicate  perfumes,  such  as  those  of 
the  jasmine,  the  violet,  the  tube  rose  and  the  orange  blos- 
som, are  thus  fixed,  and  sent  in  enormous  quantities  to  all 
parts  of  the  world  in  the  form  of  pomades  or  oils.  In  the 
latter  case  the  ancient  method  of  production  is  indicated 
by  the  designation  huiles  antiques. 

Although  the  natural  fragrance  is  most  perfectly  repro- 
duced in  these  products,  their  form  is  not  suitable  for  all 
purposes.  The  favorite  form  of  flower  odors  is  that  of  the 
volatile  "perfumery,"  so  called,  with  which  garments, 
handkerchiefs,  gloves,  etc.,  can  be  moistened,  which  would 
of  course  be  impossible  with  the  oils  and  pomades.  This 
perfumery,  technically  called  "extracts"  or  "spirits," 
results  from  a  simple  process  of  shaking  .the  pomades  and 
huiles  antiques  with  pure  alcohol,  which  does  not  dissolve 
fats  or  fixed  oils,  but  upon  continued  and  intimate  contact 
absorbs  the  incorporated  fragrance  and  becomes  entirely 
saturated  with  it.  The  alcohol  is  mechanically  separated 
from  the  oil  by  filtration,  and  a  double  product  is  obtained 
—an  alcoholic,  perfectly  volatile  and  pure  "extract"  and 
a  residue  of  weak  but  pleasantly  fragrant  and  utilizable 
fat  or  oil. 


NATURAL  AND  ARTIFICIAL  PERFUMES     133 

The  above  described  method  of  immersing  flowers  in 
fatty  substances  is  called  "maceration";  it  is  the  most 
primitive  and  without  doubt  the  most  ancient  process,  but 
it  has  many  disadvantages,  among  which  may  be  reckoned 
first  of  all  the  loss  of  the  oil  adhering  to  the  flowers. 
Efforts  have  constantly  been  made,  therefore,  to  replace 
this  method  by  a  more  perfect  one.  In  the  so-called  "en- 
fleurage"  the  flowers  do  not  come  into  direct  contact  with 
the  liquid  or  solid  fat;  frames  covered  with  gauze  are 
placed  above  one  another  in  cupboards  which  admit  of 
being  closed,  and  upon  these  frames  are  placed  alternately 
a  stratum  of  purified  and  pulverized  fat  and  a  layer  of 
flowers.  By  means  of  a  current  of  air,  the  perfume  of 
the  flowers  is  conveyed  to  the  fat,  and  after  repeated 
renewals  there  is  obtained  a  pomade  of  a  strong  and 
natural  flower  odor,  which  can  be  treated  with  alcohol  to 
make  extracts. 

This  method  not  only  has  many  technical  advantages, 
but  it  permits  first  of  all  a  more  complete  utilization  of 
the  odorous  plants.  Since  the  flowers  do  not  come  into 
contact  with  the  fat,  they  exhale  their  fragrance  as  long 
as  they  have  any  vitality,  that  is,  the  fragrant  secretions 
are  continued  for  a  time  after  separation  from  the  stem, 
and  by  the  "enfleurage"  process  can  be  brought  into 
effect.  Accurate  analytical  tests  have  of  late  led  to  the 
belief  that  seven  times  as  much  of  the  odorous  substance 
of  jasmine  can  be  obtained  in  this  way  as  by  direct  extrac- 
tion with  liquid  fat  which  quickly  destroys  the  vital  func- 
tions of  the  plant. 

In  spite  of  this,  the  extraction  of  the  odorous  elements 
is  still  an  important  process,  especially  in  cases  where  they 
exist  in  tangible  quantities,  and  also  where  they  are  to  be 
obtained  from  dried  portions  of  plants,  from  seeds  or 
roots,  instead  of  from  the  plant  in  bloom.  The  best  of 
results  have  been  reached  here  by  the  use  of  volatile 
extracting  agents,  such  as  petroleum  ether  and  benzin. 
With  suitable  extracting  apparatus,  the  solutions,  through 


134  MODERN  SCIENCE  READER 

evaporation  of  the  dissolving  agent,  yield  the  less  volatile 
odorous  substances  in  the  form  of  a  thin  or  thick  liquid, 
sometimes  even  of  the  consistency  of  a  salve,  mostly  color- 
less or  pale  in  color.  These  substances  are  generally 
called  essential  or  volatile  oils.  They  all  have  the  property 
of  being  entirely  volatile  with  steam,  and  for  this  reason 
they  are  easily  separated  from  other  substances.  The 
plants  are  put  into  stills  filled  with  water,  and  steam  is 
forced  through  in  such  a  way  that,  after  it  has  heated 
plants  and  liquid  to  the  boiling  point,  it  can  escape  into  a 
cooled  receiver,  where  it  is  condensed.  It  has  by  degrees 
taken  from  the  plants  all  their  essential  oil,  and  carries  it 
with  itself  into  the  receiver,  where  it  collects  in  drops  upon 
the  surface  of  the  condensed  liquid.  From  large  quan- 
tities of  the  distillate  these  drops  can  be  gathered  together 
and  separated  from  the  liquid  by  pouring  off  or  skimming. 

This  method  has  likewise  been  long  in  use  in  various 
parts  of  the  world ;  it  is  practised  in  some  places  in  a  very 
primitive  form,  and  has  made  possible  the  production  of 
a  great  number  of  fragrant  volatile  oils. 

The  very  costly  oil,  or  attar,  of  roses,  is  manufactured 
in  Persia,  and  now  especially  in  Bulgaria.  On  the  island 
of  Luzon,  in  the  Philippines,  and  in  Java  is  produced 
from  the  blossoms  of  a  tree  belonging  to  the  family  of 
Anonaceae— Cananga  odorata—tlie  no  less  exquisitely 
fragrant  oil  of  ylang-ylang,  called  in  Java,  oil  of  cananga, 
In  France  neroli  oil,  an  important  constituent  of  eau-de- 
cologne,  is  obtained  from  orange  blossoms— to  say  nothing 
of  the  numerous  oils,  less  costly,  but  still  valuable,  employed 
in  the  greatest  quantities  in  the  manufacture  of  perfum- 
ery, soaps  and  cordials,  as,  for  example,  rose-geranium, 
peppermint,  lavender,  etc. 

The  volatile  oils  produced  by  either  method  are  char- 
acterized, as  has  already  been  remarked,  by  fixed  proper- 
ties, especially  by  their  individual  and  very  strong  odor, 
which  to  a  certain  degree  can  at  once  be  distinguished 
from  any  other. 


NATURAL  AND  ARTIFICIAL  PERFUMES     135 

In  spite  of  this  they  are  very  far  from  representing 
uniform  chemical  substances;  each,  rather,  is  a  mixture 
of  several  different  substances,  some  one  of  which,  for  the 
most  part,  is  the  real  odorous  principle,  and  therefore  the 
only  valuable  one. 

The  technical  production  of  volatile  oils  having  become 
a  great  industry  of  modern  times— pursued  with  especial 
zeal  in  Germany— the  chemists  are  making  more  and 
more  strenuous  efforts  to  reach  an  understanding  of  the 
intimate  composition  of  these  substances  and  of  odorous 
substances  in  general;  and  chemical  science  has  attained 
in  this  field  the  most  notable  and  brilliant  results.  In  this 
matter  technics  and  science  have  been  obliged,  as  so  often 
before,  to  go  hand  in  hand.  The  great  firm  of  Sehimmel 
&  Co.,  for  example,  of  Leipsic,  manufacturers  of  volatile 
oils,  have  had  most  of  their  products  subjected  to  the  most 
exact  scientific  investigations,  and  in  many  cases  light  has 
been  thrown  thereby  upon  obscure  and  complex  points  of 
composition. 

Not  a  few  chemists  of  repute  have  devoted  all  their 
energies  to  this  interesting  field;  a  prominent  pathfinder, 
whose  efforts  were  attended  by  unusual  results,  was  the 
late  Professor  Ferdinand  Tiemann,  of  the  University  of 
Berlin,  who  had  most  admirable  and  astonishing  success 
with  syntheses  of  two  of  the  most  valuable  perfumes,  vanilla 
and  violet. 

Looking  at  the  results  of  these  investigations,  as  far  as 
it  is  possible  to  do  so  within  the  limits  of  our  article,  we 
shall  see  that  in  the  examination  of  single  natural  per- 
fumes they  were  quite  simple  and  comprehensible.  Liebig 
and  Wohler,  in  their  fundamental  labors,  had  already 
recognized  the  oil  of  bitter  almonds  as  the  aldehyde  of 
benzoic  acid,  and  this  was  not  only  confirmed  later  by 
synthetic  methods,  but  the  benzaldehyde  soon  became  a 
subject  of  technical  synthesis.  The  aldehyde  of  cinnamic 
acid  was  found  to  be  the  principal  constituent  of  the 
spicy  Ceylon  cinnamon  and  cassia  oil ;  and  the  methyl-ester 


136  MODERN  SCIENCE  READER 

of  salicylic  acid  almost  the  sole  constituent  of  the  fragrant 
oil  of  the  American  wintergreen  (Gaultheria  procwmbens) . 

The  artificial  production  of  such  substances  was  early 
undertaken,  and  has  tended  to  increase  their  use  by  mak- 
ing prices  lower.  A  number  of  perfumes  which  very 
perfectly  reproduce  the  odors  of  various  fruits  are  called 
fruit-ethers,  and  their  composition  has  been  known  for  a 
considerable  length  of  time.  They  are  compounds— esters, 
so  called— of  alcohols,  such  as  ethyl-alcohol,  butyl-alcohol 
and  amyl-alcohol,  with  acetic,  butyric  and  valerianic  acids; 
and  they  are  extensively  used  in  the  manufacture  of  fruit 
beverages  and  confectionery  for  the  imitation  of  all  pos- 
sible fruit  aromas. 

Researches  into  the  nature  of  these  few  comparatively 
simple  substances  comprised  at  first  the  whole  of  our 
chemical  knowledge  of  the  subject,  and  it  was  a  long  time 
before  further  information  was  gained  in  regard  to  the 
complex  odorous  elements.  It  seemed  at  first  as  if  a 
hydrocarbon,  C10  H16,  were  a  common  and  characteristic 
constituent  of  a  large  proportion  of  the  essential  oils;  but 
it  was  soon  discovered  that  this  substance,  isolated  from 
the  different  oils,  showed,  with  the  same  composition  in 
point  of  percentage,  entirely  different  physical  properties, 
and  above  all  things  did  not  determine  their  odor.  The 
essential  and  very  important  practical  question  of  the 
characteristic  odorous  principle  of  each  volatile  oil  was 
thus  little  advanced  and  was  the  chief  point  of  interest  in 
all  researches.  The  investigators  were  led  in  the  main  to 
observe  the  oils  of  similar  odor  in  groups,  and  to  look  for 
them  according  to  their  common  constituents.  For  exam- 
ple, the  costly  oil  of  roses,  valued  sometimes  at  one  thou- 
sand marks  and  more  per  kilo,  is  unmistakably  similar  in 
odor  to  a  very  inexpensive  oil  obtained  from  a  species  of 
East  Indian  grass,  Andropogon  schoenanthus,  and  also  to 
geranium  oils  distilled  from  different  species  of  Pelargon- 
ium, in  Spain  and  North  Africa,  particularly  at  Reunion. 
This  resemblance  was  well  enough  known  to  the  old 


NATURAL  AND  ARTIFICIAL  PERFUMES    137 

Oriental  producers  of  oil  of  roses,  and  was  probably  of  less 
interest  to  them  from  a  scientific  standpoint  than  on  ac- 
count of  the  opportunity  thus  offered  of  adulterating  the 
costly  liquid,  a  practice  always  willingly  and  extensively 
followed. 

As  a  matter  of  fact,  there  has  been  very  recently  pro- 
duced from  all  these  oils  a  common,  nearly  if  not  quite 
identical,  substance,  called  by  different  investigators 
geraniol,  rhodinol,  or  reuniol ;  and  chemists  are  inclined 
to  regard  it  as  the  essential  odorous  principle  of  oil  of 
roses.  It  is  not  yet  equal  in  abundance  and  character  to 
the  oil  of  roses,  but  it  is  believed  that  only  a  few  trifling 
additions  are  needed  to  make  it  so.  The  very  latest  re- 
searches claim  the  discovery  of  the  required  substances  in 
the  so-called  phenyl-ethyl-alcohol,  and  in  the  aldehyde  of 
nonylic  and  decylic  acids,  and  there  is  already  upon  the 
market  an  artificial  oil  of  roses,  prepared  according  to 
these  formulae. 

Similar  perhaps,  even  finer,  results,  had  before  been 
reached  in  the  production— or,  more  correctly  speaking, 
imitation — of  another  costly  perfume,  the  oil  of  jasmine. 
It  was  proved  that  this  oil,  obtainable  from  the  blossoms 
in  very  small  quantities,  consists  essentially  of  the  familiar 
benzyl-alcohol  and  an  acetate  of  benzyl,  which,  in  an  undi- 
luted state,  has  a  very  strong  flower  fragrance;  together 
with  two  or  three  per  cent,  of  a  substance,  discovered  in- 
deed some  time  ago,  but  not  sufficiently  regarded  in  point 
of  odorous  properties.  The  latter,  which  can  be  produced 
in  beautiful  white  crystals  by  the  combination  of  methyl- 
alcohol  (wood  spirits)  with  anthranilic  or  ortho-amido- 
benzoic  acid,  has  so  distinct  and  intense  a  fragrance  of 
orange  blossoms  that  with  its  aid  an  artificial  orange  blos- 
som oil  has  been  manufactured  which  is  almost  equal  to  the 
very  valuable  natural  product,  and  seems  qualified  to  enter 
into  strong  competition  with  it. 

With  the  above-described  substances  it  was  evidently  a 
matter  of  copying,  so  to  speak,  a  complex  perfume  by  a 


138  MODERN  SCIENCE  READER 

compound    of    already    known    odorous    substances;    and 
although  this   was   in   a   certain   degree   successful   in   the 
case  of  jasmine  oil,  neroli  oil,  and  even  oil  of  roses,  yet  in 
none  of  these  cases  was  the  real  odor-bearer  detected  and 
named  with  certainty.     There  was  only  a  combination  of 
several  substances,  which,  with  manifold  variations  of  their 
compound   perfume,   imitated   more   or   less  perfectly   the 
fragrance  of  the  orange  blossom,  the  rose  and  the  jasmine. 
But  Ferdinand  Tiemann  had  already  succeeded  in  produc- 
ing,  by   pure   scientific   synthesis,   the   first    characteristic 
precious   perfume,   the   substance   whose   delicate   lustrous 
crystal  needles  cover  the  pods  of  the  vanilla  bean,  and  give 
it  the  delicious  fragrance  especially  esteemed  by  northern 
nations.     This  was  recognized  as  the  methyl-ether  of  the 
aldehyde  of  protocatechu,  and  Tiemann  produced  it   (an 
enigma  to  the  unscientific  mind)  from  the  sap  or  pitch  of 
our  native  pine.     It  was  very  soon  employed  technically. 
In  regard  to  the  value  of  such  substances,  it  is  interesting 
to  know  that  this,  on  its  appearance  in  commerce,  was  sold 
for  not  less  than  six  thousand  marks  per  kilo.     The  price 
long  remained   coiite   high,   but   advancing  technics   soon 
learned  to  replace  the  first  method  of  its  production  by  a 
cheaper  one,  which  is  always  the  case  when  the  composition 
and  decompositions  of  a  chemical  substance  have  once  been 
accurately  learned  and  studied  in  all  their  bearings.     To- 
day  vanillin   is   exclusively   manufactured   from    eugenol, 
abundantly  present  in  the  inexpensive   oil  of  cloves  and 
chemically  related  to  it.     To  the  sorrow  of  all  manufac- 
turers and  patentees,  the  price  has  gone  down   from  six 
thousand   marks   per   kilo    to   sixty    in    a    few   years.     A 
hundred   times   as   much   can   thus   be   had   for  the   same 
money   as   in   the   first   years   of   its   production,    and   the 
use  of  vanilla  for  perfumes,  foods  and  beverages  is  practic- 
able  to    a    degree    formerly    impossible.     Similar    changes 
have  taken  place  in  the  prices  of  other  perfumes  which 
science  has  made  accessible,  as,  for  example,  piperonal,  or 
heliotropin,    the    odorous    principle    of    heliotrope,    which 


NATURAL  AND  ARTIFICIAL  PERFUMES     139 

resembles  vanilla,  and  is  related  to  it  in  chemical  composi- 
tion. Other  examples  of  such  technical  achievements  are 
coumarin,  which  perfectly  reproduces  the  odor  of  the  fra- 
grant herb  called  woodruff  (Waldmeister)  and  lends  its 
characteristic  aroma  to  many  a  spicy  brew,  and  terpineol, 
obtained  from  ordinary  turpentine  oil,  which  has  an  ex- 
tremely strong  odor  of  lilacs,  and  is  an  indispensable 
adjunct  to  all  modern  lilac  perfumes;  to  say  nothing  of 
the  cheaper  and  more  ordinary  perfumes,  such  as  safrol, 
nitrobenzol,  etc. 

To  name  all  would  lead  us  too  far ;  but  we  must  not  leave 
unmentioned  one  discovery,  that  of  the  artificial  violet  per- 
fume, the  last  important  work  of  Tiemann.  Starting  from 
the  analyses  of  orris-root,  the  rhizoma  of  a  species  of  lily, 
Iris  florentina,  in  which  he  suspected  the  existence  of  the 
genuine  aroma  of  violets,  he  succeeded  through  his  wonder- 
ful gift  of  combination  in  condensing  with  acetone  the  so- 
called  citral  contained  in  lemon-rind  and  some  other 
volatile  oils,  and  obtained  a  substance  which  he  called 
pseudo-ionon.  Under  the  action  of  dilute  sulphuric  acid 
this  is  changed  to  the  real  ionon,  which,  in  a  thousand-fold 
dilution  with  pure  alcohol,  exhales  a  delicious  and  natural 
fragrance  of  violets,  and  is  the  foundation  of  the  favorite 
violet  perfumes,  whose  use  has  been  so  widely  extended 
since  the  discovery. 

Our  subject  would  now  be  nearly  exhausted  but  for  one 
remarkable  substance,  which  must  not  be  forgotten,  arti- 
ficial musk.  Baur,  its  fortunate  discoverer,  found,  about 
fifteen  years  ago,  that  if  toluol  and  butylic  chloride  are 
combined  according  to  the  well-known  chemical  method  of 
Friedel  and  Craffts,  and  the  resulting  oil  treated  with 
highly-concentrated  nitric  acid,  the  so-called  "trinitro- 
butyl-toluol' '  is  obtained  in  pretty  crystals,  which  have  an 
odor  of  musk  wonderful  in  quantity  and  intensity.  When 
we  remember  that  the  natural  musk— a  secretion  of  an 
animal  of  the  deer  family,  native  to  the  interior  of  Asia- 
is  a  very  costly  and  extensively  used  substance,  sold  for 


140  MODERN  SCIENCE  READER 

more  than  three  thousand  marks  per  kilo,  we  shall  become 
conscious  of  the  economic  bearings  of  this  and  analogous 
discoveries.  Scientifically  considered,  the  manufacture  of 
artificial  musk  does  not  stand  upon  the  same  plane  as  the 
synthetic  construction  of  vanillin,  coumarin,  or  ionon. 
With  these  substances  the  chemist  has  succeeded  in  dis- 
covering, by  dint  of  laborious  researches,  their  correct  com- 
position, and  has  then  reproduced  the  natural  product  in 
a  more  advantageous  way.  Perfumes,  on  the  other  hand, 
like  mirbane  oil  or  artificial  musk  are  simply  imitations  of 
the  corresponding  natural  substances,  and  chemically  unre- 
lated to  them. 


SCIENTIFIC  DEVELOPMENTS  IN  THE 
GLASS  INDUSTRY1 

BY   DR.   R.   SCHALLEE 

THE  manufacture  of  glass  involves  first  the  chemical 
process  of  producing  glass  from  the  proper  raw  materials, 
and  secondly  the  mechanical  art  of  fashioning  the  molten 
glass  into  the  multitude  of  articles  for  which  the  market 
calls.  The  mechanical  aspect  of  the  industry  was  early 
developed  to  a  high  state  of  perfection.  It  is  only  within 
comparatively  recent  times,  on  the  other  hand,  that  the 
chemistry  of  glass  making  has  been  worked  out  with  scien- 
tific method.  The  need  for  such  a  development  first  made 
itself  felt  with  special  force  in  connection  with  the  manu- 
facture of  optical  instruments,  and  it  is  largely  this  cir- 
cumstance which  caused  the  famous  Jena  Glass  Works  to 
undertake  the  systematic  study  of  the  physical  and  chem- 
ical properties  of  glass. 

The  influence  of  the  composition  of  glass  on  its  proper- 
ties is  best  brought  out  by  a  graphic  representation.  Thus 
in  Fig.  1,  distances  measured  off  to  the  right,  along  the 
axis  of  the  abscissae,  represent  the  composition  of  a  soda 
glass,  while  the  corresponding  ordinates  represent  tempera- 
tures. The  curve  drawn  out  in  a  full  line  shows  the  upper 
limiting  temperature  of  devitrification.  This  means  that 
a  soda  glass  of  a  given  composition  remains  glassy  provided 
it  is  not  cooled  below  that  point  on  the  curve,  which  cor- 
responds to  the  particular  composition  of  the  glass.  Thus 
for  example  a  glass  containing  about  75  per  cent,  of  silica 
(Si02)  and  25  per  cent,  of  soda  (Na20)  can  be  cooled  to 

Abstracted  from  a  paper  read  before  the  Verein  deutscher 
Chemiker  at  Frankfort,  a.  M.  From  Scientific  American  Supplement 
No.  1797,  June,  1910. 

141 


142  MODERN  SCIENCE  READER 

nearly  700°  C.  without  devitrifying.  The  significance  of 
this  curve  is  obvious  when  we  consider  that  in  working 
the  glass  it  must  be  brought  down  to  a  temperature  at 
which  it  possesses  a  sufficient  degree  of  tenacity.  The 
dotted  line  on  Fig.  1  indicates  points  of  equal  tenacity. 
It  will  be  seen  that  at  temperatures  corresponding  to  this 
particular  tenacity,  glasses  of  certain  compositions  are  be- 
low the  temperature  required  to  keep  them  from  devitrify- 
ing. They  cannot  therefore  safely  be  cooled  down  to  this 
degree  of  tenacity.  Others,  in  a  small  region  extending 
about  from  seventy-one  to  seventy-six  per  cent.  Si02,  are 
above  that  temperature,  and  will  therefore  remain  glassy 
if  cooled  till  they  have  the  tenacity  corresponding  to  the 
dotted  line. 

The  pure  soda  glasses  cannot  be  used  for  the  general 
purposes  to  which  "glass"  is  put,  as  they  are  water- 
soluble.  The  second  diagram  shows  some  of  the  properties 
of  a  lime-soda  glass,  such  as  we  have  for  example  in 
window  glass.  In  this  diagram  the  ordinates  represent 
the  proportion  of  soda  (Na20),  and  the  abscissae  proportion 
of  lime  (CaO).  It  is  understood  throughout  that  the 
proportion  of  silica  (Si02)  is  100.  The  lines  drawn  out  in 
full  are  lines  of  equal  stability,  the  numerals  2,  3,  5  repre- 
senting increasing  degrees  of  instability.  The  dotted  lines 
correspond  to  equal  temperatures  of  devitrification.  The 
compositions  suitable  for  window  glass  are  those  comprised 
within  the  field  bounded  below  by  one  of  these  dotted  lines, 
and  above  by  one  of  the  full  lines.  For  if  we  step  outside 
this  region,  either  the  temperature  of  devitrification  is  too 
high,  so  that  the  glass  cannot  be  cooled  down  to  a  working 
temperature,  or  else  the  glass  is  too  unstable. 

In  addition  to  lime  and  soda,  many  glasses  contain 
also  alumina  or  boron  trioxide.  The  effect  of  these  con- 
stituents is  to  increase  the  stability  of  the  glass.  In  the 
case  of  alumina  this  is  probably  due  to  the  formation  of 
double  silicates  of  the  type  of  feldspar.  The  beneficial 
influence  of  the  boric  oxide  is  probably  due  to  another 


DEVELOPMENTS  IN  GLASS  INDUSTRY      143 

cause:  this  body  functions  as  an  acid,  setting  free  silica. 
As  has  already  been  pointed  out,  the  physical  and  chem- 
ical investigations  at  the  Jena  Glass  Works  were  in  the  first 


&o3 

s/oo* 
/ooo 

600* 
700* 

/ 

< 

1 

1 

< 

! 

^ 

/ 

.  \ 

\1 

JL_^ 

/ 

jy 

\^ 

OO            ?O               QO               7O              60              SO  <fi* 
0              /O               20             JO             +0             W/{> 

.  Upper  limiting  temperature  of  devitrification 

_____  Curve  of  equal  tenacity 
FIG.  1 

place  aimed  chiefly   for  the   production   of  new   optical 
glasses.     All  tHe  glasses  known  in  the  earlier  days  were 


144  MODERN  SCIENCE  READER 

somewhat  similar  in  their  optical  properties.  That  is  to 
say,  while  their  refractive  index  and  dispersive  power 
varied  within  certain  limits,  they  ran  parallel  throughout, 
so  that  if  the  known  glasses  were  arranged  in  order  of 
increasing  refractive  index,  this  would  at  the  same  time 
place  them  in  the  order  of  their  dispersive  powers.  Glasses 
were  needed  which  should  not  conform  to  this  order,  and 
it  was  found  that  especially  barium  and  zinc  possessed  in 
a  high  degree  the  property  of  imparting  to  glass  a  high 
refractive  index,  accompanied  by  a  comparatively  low  dis- 
persive power. 

Another  problem  was  to  prepare  crown  and  flint  glass 
which  would  give  as  nearly  as  possible  similarly  propor- 
tioned spectra.  The  flint  glasses  then  known  gave  a  spec- 
trum which  was  much  more  drawn  out  in  the  blue  than 
that  produced  by  crown  glass.  The  remedy  was  found  in 
the  addition  of  boric  oxide,  which  foreshortens  the  blue  end 
of  the  flint-glass  spectrum. 

Another  class  of  optical  glasses  are  the  colored  glasses. 
The  principal  problem  in  the  preparation  of  these  is  to 
produce  as  nearly  as  possible  ideal  color  niters.  Such  a 
glass  must  absorb  as  completely  as  possible  some  particular 
portion  of  the  spectrum,  while  transmitting  the  remainder. 
The  materials  added  to  give  the  requisite  color  are  the 
oxides,  sulphides  and  selenides  of  certain  metals,  or  in  cer- 
tain cases  the  metal  itself  in  a  highly  divided  state.  The 
color  imparted  by  such  additions  depends  in  part  on  the 
composition  of  the  glass  in  which  they  are  dissolved. 

A  problem  of  the  same  character  is  the  preparation  of 
glasses  which  transmit  very  short  wave  lengths  of  light. 
It  is  well  known  that  quartz  and  boric  acid  have  the  prop- 
erty of  being  transparent  to  ultra-violet  rays.  The  pres- 
ence of  metallic  oxides  more  or  less  completely  destroys 
this  property,  the  extent  to  which  this  takes  place  depend- 
ing on  the  nature  of  the  metal,  thus  sodium  has  a  stronger 
effect  than  potassium,  while  lead  glasses  are  particularly 
opaque  to  short  wave  lengths.  However,  by  carefully 


DEVELOPMENTS  IN  GLASS  INDUSTRY      145 


observing  certain  precautions,  it  is  possible  to  prepare 
silicate  glasses  of  much  greater  transparency  to  ultra-violet 
light  than  common  glass.  A  special  product  of  this  char- 
acter made  by  the  Jena  works  and  marketed  under  the 


/O 


/O 


J 


CaO 


11    Curve  of  equal  stability 
....-.-.    Curve  of  equal  devitrifying  temperature 

FIG.  2 

name  of  "uviol  glass"  has  found  application  especially  in 
astro-photography  and  in  the  manufacture  of  the  uviol 
mercury  lamp.  This  latter,  as  our  readers  may  remember, 
is  used  for  medical  purposes  in  the  treatment  of  skin 
diseases,  and  in  certain  chemical  industries,  especially  in 
the  production  of  linseed  oil  products. 
10 


146  MODERN  SCIENCE  READER 

Another  property  of  glass  which  is  of  great  importance 
in  connection  with  certain  of  its  applications  is  its  behavior 
toward  changes  of  temperature.  If  a  hot  glass  article, 
while  still  soft,  is  allowed  to  cool  quickly,  inequalities  in 
density  are  produced  within  the  mass  of  glass,  giving  rise 
to  internal  strains.  A  glass  tube,  for  this  reason,  is  always 
under  a  peripheral  compressing  strain,  while  the  inside  is 
under  tension.  The  consequence  of  this  is  a  high  resistance 
to  mechanical  injury  on  the  outside,  while  any  scratch  on 
the  inside,  especially  in  the  case  of  thick  walled  tubes,  al- 
most inevitably  leads  to  the  cracking  of  the  tube.  Such 
tubes  in  which  the  outer  wall  is  under  a  compressing  strain 
and  the  inner  wall  under  tension  nevertheless  possess  cer- 
tain advantages  over  tubes  free  from  strain.  For  if  such 
a  tube  is  heated  from  within  to  a  temperature  considerably 
exceeding  that  of  its  surroundings,  the  thermal  expansion 
of  the  inner  layers  must  first  neutralize  the  existing  tension 
before  the  tube  can  acquire  any  tangential  expansion  strain 
tending  to  burst  the  tube.  Such  a  tube  can  therefore  with- 
stand considerably  higher  differences  of  temperature  be- 
tween its  inner  and  outer  surface  than  a  tube  initially  free 
from  strain.  The  same  advantage  is  gained  where  the 
tube  is  to  be  subjected  to  pressure  from  within,  as  in  water 
gages  for  boilers.  For  this  purpose  tubes  free  from  strain 
cannot  be  used  at  all.  The  sensitiveness  of  the  inner  wall 
may  be  prevented  by  making  the  tube  of  two  layers  having 
a  different  coefficient  of  expansion  with  temperature. 
Tubes  of  this  kind  are  largely  employed  for  boiler  gages. 

A  glass  having  a  very  low  coefficient  of  expansion  will 
cool  without  acquiring  any  appreciable  strain.  Such  a 
glass  is  particularly  well  adapted  to  resist  sudden  temper- 
ature changes  and  is  used  for  example  in  making  chimneys 
for  incandescent  gaslight.  Another  purpose  for  which 
glass  possessing  special  properties  is  required  is  the  con- 
struction of  thermometers.  One  of  the  errors  to  which 
thermometers  are  subject  is  the  apparent  lowering  of  the 
freezing  point  if  the  latter  is  observed  soon  after  the 


DEVELOPMENTS  IN  GLASS  INDUSTRY      147 

thermometer  has  been  used  to  measure  a  high  temperature. 
Experiments  showed  that  the  simultaneous  presence  of  pot- 
ash and  soda  is  particularly  responsible  for  a  large  error 
of  this  character.  Finally,  the  brand  known  as  Jena  nor- 
mal thermometer  glass  16  III  was  evolved,  and  this  is  now 
regularly  manufactured  in  uniform  quality.  It  is  com- 
monly formed  with  a  red  streak  to  render  it  readily  dis- 
tinguishable. Its  coefficient  of  expansion  is  so  nearly  alike 
to  that  of  platinum  that  the  metal  can  be  fused  into  it, 
making  a  gas-tight  joint.  Another  special  thermometer 
glass  is  the  boron  glass  59  III,  which  is  particularly  well 
adapted  for  high  temperature  thermometers  ranging  up  to 
500°  C.  This  glass  is  even  superior  to  the  first  mentioned, 
having  a  lower  coefficient  of  expansion.  This,  however, 
brings  with  it  the  disadvantage  that  a  gas-tight  joint  with 
platinum  cannot  be  made  through  it  by  fusion. 

In  conclusion  it  may  be  said  that  the  principal  char- 
acteristic of  the  advances  made  at  the  Jena  works  during 
the  last  twenty-five  years  consist  in  the  production  of 
special  glass  adapted  for  definite  purposes.  This  was 
rendered  possible  only  by  greatly  increasing  the  variety  of 
types  of  glass  prepared  and  by  the  utilization  of  elements 
which  previously  had  not  been  employed  in  glass  making. 
Nevertheless,  had  the  demand  been  exclusively  for  glasses 
for  scientific  purposes,  this  would  never  have  been  sufficient 
to  enable  the  manufacturer  to  meet  the  requirements  and 
at  the  same  time  secure  a  margin  of  profit.  The  com- 
mercial possibility  of  the  developments  which  have  taken 
place  necessarily  rested  on  their  exploitation  for  general 
technical  purposes,  as  for  example  in  the  manufacture  of 
the  Jena  incandescent  gas-light  chimneys. 


WHAT  ELECTROCHEMISTRY  IS 
ACCOMPLISHING1 

BY  PKOFESSOE  JOSEPH  W.  EICHAKDS 

MY  theme  is  to  depict  for  you,  as  clearly  as  I  may  be 
able,  the  part  which  electrochemistry  is  playing  in  modern 
industrial  processes.  I  have  no  exhaustive  catalog  of 
electrochemical  processes  to  present,  nor  columns  of  statis- 
tics of  these  industries;  but  my  object  will  be  to  classify 
the  various  activities  of  electrochemists  and  to  analyze  the 
scope  of  the  electrochemical  industries. 

Electrochemistry  is  the  art  of  applying  electrical  energy 
co  facilitating  the  work  of  the  chemist.  It  is  chemistry 
helped  by  electricity.  It  is  the  use  of  a  new  agency  in 
accomplishing  chemical  operations,  and  it  has  not  only 
succeeded  in  facilitating  many  of  the  most  difficult  and 
costly  of  chemical  reactions,  but  it  has  in  many  cases  sup- 
planted them  by  quick,  simple  and  direct  methods;  it  has 
even,  in  many  cases,  developed  new  reactions  and  produced 
new  materials  which  are  not  otherwise  capable  of  being 
made.  A  few  examples  will  illustrate  these  points :  Caustic 
soda  and  bleaching  powder  are  made  from  common  salt  by 
a  series  of  operations,  but  the  electrical  method  does  this 
neatly  and  cheaply  in  practically  one  operation ;  lime  and 
carbon  do  not  react  by  ordinary  chemical  processes,  but 
in  the  electric  furnace  they  react  at  once  to  form  the  valu- 
able and  familiar  calcium  carbid;  carbon  stays  carbon  ex- 
cept when  the  intense  heat  of  the  electric  furnace  converts 
it  into  artificial  graphite.  The  list  of  such  operations  is  a 
long  one,  and  it  may  be  said  that  the  chemist  has  become  a 

1  An  address  before  the  American  Electrochemical  Society,  in 
Pittsbnrg.  Published  in  vol.  xvii  (1910)  of  the  Transactions  of  that 
society. 

148 


ELECTROCHEMISTRY  149 

much  more  highly  efficient  and  accomplished  chemist  since 
he  became  an  electrochemist,  and  he  is  becoming  more  of 
an  electrochemist  daily. 

Electrometallurgy  applies  electric  energy  to  facilitating 
the  solution  of  the  problems  confronting  the  metallurgist. 
Its  birth  is  but  recent,  yet  it  has  rendered  invaluable  serv- 
ice ;  it  has  made  easy  some  of  the  most  difficult  extractions, 
has  produced  several  of  the  metals  at  a  small  fraction  of 
their  former  cost,  and  has  put  at  our  disposal  in  com- 
mercial quantities  and  at  practicable  prices  metals  which 
were  formerly  unknown  or  else  mere  chemical  curiosities. 
It  has,  further,  refined  many  metals  to  a  degree  of  purity 
not  previously  known.  The  metallurgist  is  rapidly  appre- 
ciating the  possibilities  of  electrometallurgical  methods, 
and  they  already  form  a  considerable  proportion  of  present 
metallurgical  practice. 

Applied  electrochemistry,  covering  in  general  all  of  the 
field  just  described,  is  therefore  an  important  part  of 
chemistry  and  metallurgy,  and  is  rapidly  increasing  in 
importance.  It  is  a  new  art,  people  are  really  only  begin- 
ning to  understand  its  principles  and  to  appreciate  its 
possibilities ;  it  is  an  art  pursued  by  the  most  energetic  and 
enterprising  chemists,  with  the  assistance  of  the  most 
skilled  electricians.  Some  of  its  most  prominent  exponents 
are  electrical  engineers  who  have  been  attracted  by  the  vast 
possibilities  opened  up  by  these  applications  of  electricity. 
The  chemists  have  worked  with  electricity  like  children 
with  a  new  toy,  or  a  boy  with  a  new  machine;  they  have 
had  the  novel  experience  of  seeing  what  bonders  their 
newly  applied  agency  could  accomplish,  and  it  is  no 
exaggeration  to  say  that  they  have  astonished  the  world 
—and  themselves. 

THE  AGENTS  OF  ELECTROCHEMISTRY 

The  operating  agent  in  electrochemistry  is,  of  course, 
electric  energy,  which  may  be  used  in  three  classes  of 
apparatus,  viz. : 


150  MODERN  SCIENCE  READER 

(I)     Electrolytic  Apparatus. 
(II)     Electric  Arcs  and  Discharges  in  Gases. 
(Ill)     Electric  Furnaces. 

7.  Electrolytic  Apparatus 

Electrolytic  apparatus  and  processes  use  or  utilize  the 
separating  or  decomposing  power  of  the  electric  current. 
Whenever  an  electric  current  is  sent  through  a  liquid  ma- 
terial which  is  compound  in  its  nature,  i.  e.,  a  chemical 
compound,  the  current  tends  to  decompose  the  compound 
into  two  constituents,  appearing  respectively  at  the  two 
points  of  contact  of  the  electric  conducting  circuit  with 
the  liquid  in  question,  i.  e.,  at  the  surface  or  face  of  con- 
tact of  the  undecomposable  conducting  part  of  the  circuit 
with  the  decomposable  part.  If  the  current  has  a  definite 
direction  the  constituents  appear  at  definite  electrodes.  The 
action  is  simply  the  result  of  the  current  extracting  (or 
tending  to  extract)  from  the  electrolyte  one  of  its  constit- 
uents at  each  of  the  two  electrode  surfaces.  All  subse- 
quent changes  following  upon  this  primary  tendency  of 
the  current  are  called  secondary  reactions,  and  are  prac- 
tically simultaneous  with  the  primary.  These  may  even 
be  regarded  as  truly  primary  reactions  also,  the  primitive 
decomposing  or  separating  power  of  the  current  passing 
being  regarded  only  as  a  tendency  or  a  determining  cause 
which  practically  results  in  the  reactions  actually  taking 
place. 

This  agency  is  an  extremely  vigorous  and  potent  force 
for  producing  chemical  transformations.  It  enables  us,  for 
instance,  to  split  up  some  of  the  strongest  chemical  com- 
pounds into  their  elementary  constituents,  to  convert  cheap 
materials,  in  short,  to  perform  easily  some  very  difficult 
chemical  operations,  and  in  some  cases  to  perform  chemical 
operations  otherwise  impossible.  A  description  of  all  these 
various  processes  would  take  a  volume,  but  a  short  explana- 
tion of  a  few  of  them  will  make  the  principles  clear  and 
suffice  for  my  present  purpose. 


ELECTROCHEMISTRY  151 

Electrolysis  of  Water:  As  a  raw  material,  water  may 
be  said  to  cost  nothing.  Apply  an  electric  current  to  it  in 
the  proper  way,  and  it  is  resolved  into  its  constituent  gases, 
hydrogen  and  oxygen,  as  cleanly  and  perfectly  as  any  one 
could  desire.  These  gases  have  many  and  various  uses, 
and  are  valued  each  at  several  cents  per  pound.  A  whole 
industry  has  thus  grown  up,  based  on  the  simple  electrol- 
ysis of  water,  to  supply  these  two  gases  for  various  indus- 
trial uses.  Europe  possesses  many  of  these  plants;  there 
are  a  few  in  the  United  States.  The  speaker  has  trans- 
lated from  the  German  a  small  treatise  on  this  industry. 

Electrolysis  of  Salt:  Common  salt,  sodium  chloride,  is 
one  of  the  cheapest  of  natural  chemicals.  It  has  some  uses 
of  its  own,  but  centuries  ago  chemists  and  even  alchemists 
devised  chemical  processes  for  transforming  it  into  other 
sodium  salts,  caustic  soda  or  soda  lye,  for  use  in  soap,  soda 
ash  or  carbonate,  for  washing  or  glassmaking,  and  into 
chlorine  bleaching  materials.  Chemical  works  operating 
these  rather  complicated  chemical  processes  exist  on  an 
immense  scale  in  all  civilized  countries;  it  is  estimated  that 
$50,000,000  is  thus  invested  in  Great  Britain  alone.  The 
electrolytic  alkali  industry  is  barely  twenty  years  old,  yet 
it  is  already  more  than  holding  its  own  with  the  older 
chemical  process,  and  advancing  rapidly;  twenty  years 
more  will  probably  see  the  older  processes  entirely  super- 
seded— they  are  at  present  fighting  for  their  existence.  As 
for  the  electrolytic  process,  the  salt  is  simply  dissolved  in 
water  and  by  the  action  of  the  current  converted  into 
caustic  soda  at  one  electrode  and  chlorine  gas  at  the  other. 
By  some  special  devices  these  are  kept  separate  and  col- 
lected by  themselves,  and  the  work  is  done.  The  principles 
involved  are  simplicity  itself  as  compared  with  the  older 
chemical  processes,  the  only  agent  consumed  is  electric 
energy,  and  the  products  are  clean  and  pure. 

Chlorates:  These  are  salts  used  on  matches  and  in  gun- 
powder. Chlorate  of  potassium  is  a  valuable  salt  with 
important  uses.  It  is  made  from  common  cheap  potassium 


152  MODERN  SCIENCE  READER 

chloride,  in  solution  in  water,  by  simply  electrolyzing  the 
solution  without  trying  to  separate  the  products  forming 
at  the  electrodes.  It  is  a  simpler  operation  than  the  pro- 
duction of  electrolytic  alkali.  Chlorate  thus  forms  in  the 
warm  solution,  and  is  obtained  by  letting  the  solution  cool 
and  the  chlorate  crystallize  out.  The  ordinary  chemical 
manufacture  of  this  salt  was  tedious  and  dangerous;  the 
electrolytic  method  has  practically  entirely  superseded  it. 

Per  chlorates:  These  salts  have  more  limited  uses,  but 
are  made  by  expensive  chemical  methods.  The  electrolysis 
of  a  chlorate  solution  at  a  low  temperature,  without  sepa- 
rating the  products  formed  at  the  two  electrodes,  results  in 
the  direct  and  easy  production  of  perchlorates.  I  cite  this 
more  to  illustrate  what  I  might  call  the  versatility  of  elec- 
trochemical methods,  rather  than  because  of  its  commercial 
importance. 

Metallic  Sodium:  The  caustic  soda  produced  from  salt 
can  itself  be  electrolytically  decomposed ;  this  is  the  easiest 
way  of  producing  metallic  sodium.  Sir  Humphry  Davy 
discovered  sodium  by  electrolyzing  melted  caustic  soda  and 
at  this  moment  several  large  works  are  working  this  method 
on  an  immense  scale.  The  caustic  contains  sodium,  hydro- 
gen, and  oxygen,  and  the  current  simply  liberates  the 
sodium  as  a  molten  metal  and  frees  the  other  two  as  gases, 
which  escape  into  the  air.  The  process  is  simplicity  itself 
—when  the  exact  conditions  are  known  and  rigidly  ad- 
hered to.  Metallic  sodium  is  a  very  useful  material  to  the 
chemist,  and  the  electrolytic  method  produces  it  at  probably 
one  fourth  the  cost  of  making  it  in  any  purely  chemical 
way. 

Magnesium:  This  is  a  wonderfully  light  metal,  whose 
chief  use  is  in  flash-light  powders.  Its  compounds  are 
abundant  in  nature,  but  its  manufacture  by  any  other  than 
the  electrolytic  method  is  almost  impracticable.  The  oper- 
ation consists  in  simply  passing  the  decomposing  current 
through  a  fused  magnesium  salt— a  chloride  of  magnesium 
and  potassium  found  in  abundance  in  Germany. 


ELECTROCHEMISTRY  153 

Aluminium:  The  most  useful  of  the  light  metals;  an 
element  more  abundant  in  nature  than  iron,  yet  which 
costs  by  chemical  methods  at  least  $1.00  per  pound  to  pro- 
duce; electrochemistry  enables  the  makers  to  sell  it  at  a 
profit  at  $0.25  per  pound.  This  is  probably  the. most  useful 
metal  given  to  the  world  by  electrochemistry.  Although 
the  French  chemist  Deville  obtained  it  by  an  electrolytic 
method  in  1855,  yet  he  had  only  the  battery  as  a  source  of 
electric  current,  and  the  process  was  too  costly.  This  very 
city  of  Pittsburg  was  the  real  cradle  of  the  electrolytic 
manufacture  of  aluminium,  when,  in  1889,  Mr.  Chas.  M. 
Hall,  with  the  financial  assistance  of  the  Mellons  and  the 
business  assistance  of  Capt.  A.  E.  Hunt,  commenced  to 
work  his  process  up  at  Thirty-third  Street  on  the  "West 
Side."  The  principle  of  the  process  is  here  again  one  of 
beautiful  simplicity— when  it  is  once  made  known.  Alu- 
minium oxide,  abundant  in  nature,  is  infusible  in  ordinary 
furnaces,  but  easily  melts  and  dissolves,  like  sugar  in 
water,  in  certain  very  stable  and  liquid  fused  salts— double 
fluorides  of  aluminium  and  the  alkali  metals.  On  passing 
the  electric  current  through  this  bath,  the  dissolved  alu- 
minium oxide  is  decomposed,  appearing  at  the  two  elec- 
trodes as  aluminium  and  oxygen  respectively.  When  all  the 
oxide  is  thus  broken  up,  more  is  added,  and  the  operation 
continues.  One  of  the  most  difficult  problems  of  ordinary 
chemistry  is  thus  simply,  neatly  and  effectively  solved  by 
electrochemistry.  The  lower  cost  of  power  at  Niagara 
Palls  drew  the  industry  away  from  Pittsburg,  in  1893,  and 
it  is  now  run  on  an  immense  scale  at  several  places  where 
water-power  is  cheap  and  abundant.  Mechanical  power 
is,  however,  being  produced  cheaper  every  year;  gas 
engines  have  halved  the  cost  of  such  power,  steam  turbines 
on  exhaust  steam  may  even  do  better ;  there  is  no  inherent 
impossibility  in  the  return  of  the  aluminium  industry  to 
the  Pittsburg  district.  Many  other  factors  besides  cost  of 
power  bear  on  the  question ;  cost  of  labor,  abundance  of 
labor,  cost  of  carbon,  coal  for  heating,  various  supplies, 


154  MODERN  SCIENCE  READER 

railroad  freights,  nearness  to  the  consumers,  and  many 
other  considerations  must  be  taken  into  account.  Alu- 
minium is  certainly  destined  to  become  the  most  important 
metal  next  to  iron  and  steel,  and,  as  far  as  one  can  now 
foresee,  will  always  be  produced  electrochemically.  To 
have  accomplished  the  establishment  of  this  one  single 
industry,  would  itself  have  proved  the  usefulness  of  elec- 
trical methods  and  their  importance  to  chemistry  and 
metallurgy. 

Refining  of  Metals:  Unless  metals  are  of  high  purity 
they  are  usually  of  very  little  usefulness.  Electrolytic 
methods  enable  almost  perfect  purity  to  be  easily  attained, 
and  in  addition  permit  the  separation  at  the  same  time  of 
the  valuable  gold  and  silver  contained  in  small  amount  in 
the  baser  metals.  Over  $100,000,000  worth  of  copper  is 
electrically  refined  every  year  in  the  United  States;  the 
metal  produced  is  purer  than  can  be  otherwise  obtained, 
giving  the  electrical  engineer  the  highest  grade  of  con- 
ducting metal,  while  several  million  dollars'  worth  of  gold 
and  silver  are  recovered  which  would  otherwise  have  to  be 
allowed  to  remain  in  the  copper.  Again,  the  method  is  so 
simple  that  but  a  few  words  are  necessary  to  set  it  forth 
in  principle.  The  impure  copper  is  used  as  one  electrode 
—the  anode— in  a  solution  of  copper  sulphate  containing 
some  sulphuric  acid;  the  receiving  electrode— the  cathode 
—is  a  thin  sheet  of  pure  copper,  or  of  lead,  greased.  The 
electric  action  causes  pure  copper  only  to  deposit  upon  the 
cathode,  if  a  properly  regulated  current  is  used,  while  a 
corresponding  amount  of  metal  is  dissolved  from  the  anode. 
Silver,  gold,  and  platinum  are  undissolved,  and  remain  as 
mud  or  sediment  in  the  bottom  of  the  bath ;  other  im- 
purities may  go  into  the  solution,  but  are  not  deposited  on 
the  cathode  if  the  current  is  kept  low.  The  cost  of  this 
operation  is  small,  and  the  results  are  so  highly  satisfac- 
tory that  90  per  cent,  of  all  the  copper  produced  is  thus 
refined.  Similar  methods  are  in  use  for  refining  other 
metals;  silver,  gold,  and  lead  are  thus  refined  on  a  large 


ELECTROCHEMISTRY  155 

scale;  antimony,  bismuth,  tin,  platinum,  zinc,  and  even 
iron  can  be  thus  refined;  the  field  is  very  inviting  to  the 
experimenter  and  to  the  technologist,  and  is  rapidly  in- 
creasing in  industrial  importance. 

Metal  Plating:  All  electro-plating  is  done  by  the  use 
of  electrolytic  methods  similar  to  those  just  described.  If 
we  imagine  the  impure  metal  anode  replaced  by  pure  metal, 
and  the  receiving  cathode  to  be  the  object  to  be  electro- 
plated, we  have  before  us  the  electro-plating  bath  ready 
for  action.  Everybody  knows  the  value  and  use  of  gold, 
silver,  and  nickel  plating;  less  well  known  are  platinum, 
cadmium,  chromium,  zinc,  brass,  and  bronze  plating.  These 
are  among  the  oldest  of  the  electrochemical  industries.  E'lec- 
trotyping  is  only  a  variation  of  this  work ;  also  the  electro- 
lytic reproduction  of  medals,  engravings,  cuts,  etc.,  and 
even  the  production  of  metallic  articles  of  various  and 
complicated  forms,  such  as  tubes,  needles,  mirrors,  vases, 
statues,  etc.  There  is  opportunity  here  to  hardly  more 
than  catalog  these  various  branches  of  electrometallurgical 
activity.  Pittsburg  people  will  be  interested,  however, 
in  knowing  that  many  of  the  newer  buildings  in  this  city 
contain  thousands  of  feet  of  electrical  conduits  zinc  plated 
in  splendid  fashion  by  electrolysis,  at  a  works  within  a 
few  miles  of  this  city.  At  McKeesport,  tubes  are  coated 
by  dipping  into  melted  zinc,  on  an  immense  scale,  but  the 
electrolytic  method  is  gaining  a  foothold,  and  we  may  live 
to  see  all  galvanizing  in  reality  practised  as  it  is  spelled. 
The  removing  of  metallic  tin  from  waste  tin  scrap  is  also 
accomplished  on  a  large  scale  by  the  application  of  similar 
principles.  It  is  being  operated  at  a  distance  from  Pitts- 
burg,  but  your  open-hearth  furnaces  use  up  annually 
thousands  of  tons  of  the  scrap  steel  thus  cleaned  and  saved 
for  remanufacture  into  useful  shape. 

Without  having  mentioned  or  described  more  than  a 
fraction  of  the  electrolytic  methods  in  actual  industrial 
use,  I  hope  that  I  have  made  clear  the  importance  and 
extent  of  this  kind  of  electrochemical  processes.  Assum- 


156  MODERN  SCIENCE  READER 

ing  this,  we  will  pass  to  'the  consideration  of  another, 
entirely  different  and  yet  important,  class  of  apparatus 
and  processes. 

II.  Electric  Arcs  and  Discharges  in  Gases 

Electric  arcs  and  high-tension  discharges  through  gases 
are  capable  of  producing  some  chemical  compositions  and 
decompositions  which  are  very  useful,  and  profitable  to 
operate.  This  is  a  branch  of  electrochemistry  which  has 
not  been  as  thoroughly  studied  as  some  others,  its  phe- 
nomena are  not  as  thoroughly  under  control  as  electrolysis 
and  electro-thermal  reactions,  and  its  possibilities  are  not 
as  thoroughly  understood  or  utilized. 

Ozone  is  being  made  from  air  by  the  silent  discharge  of 
high-tension  electric  current.  The  apparatus  is  so  far 
simplified  as  to  be  made  in  small  units  suitable  for  house- 
hold use,  ready  to  attach  to  a  low-tension  alternating  cur- 
rent supply.  The  uses  for  the  ozone  thus  produced  are 
particularly  for  purifying  water  and  air ;  it  makes  very 
impure  water  perfectly  safe  to  drink,  and  purifies  the  air 
of  assembly  halls  and  sick-rooms,  acting  as  an  antiseptic. 
According  to  all  appearances,  this  electrochemical  doubling 
up  of  oxygen  into  a  more  efficient  oxidizing  form  is  devel- 
oping into  a  simple  and  highly  efficient  aid  to  healthy  living. 

Nitric  Acid  is  an  expensive  acid  made  from  the  natural 
alkaline  nitrate  salts,  such  as  Chili  saltpeter.  These 
nitrates  are  the  salvation  of  the  agriculturist,  for  they 
furnish  the  ground  with  the  necessary  nitrogen  which 
plants  can  assimilate.  The  Chili  "nitrate  kings"  have 
gained  many  millions  of  dollars,  even  hundreds  of  millions, 
in  thus  supplying  the  world's  demand  for  fertilizer.  But, 
electrochemistry  has  another  solution  to  this  problem,  which 
is  rapidly  rendering  every  country  which  adopts  it  inde- 
pendent of  the  foreign  fertilizer.  The  air  we  breathe  con- 
tains tmcombined  nitrogen  and  oxygen  gases,  which  if 
combined  and  brought  into  contact  with  water  furnish  the 
exact  constituents  of  nitric  acid.  The  way  to  do  this  has 


ELECTROCHEMISTRY  157 

been  laboriously  worked  out,  and  the  electric  arc  is  the 
agent  which  does  it.  Air  is  simply  blown  into  the  electric 
arc,  where  it  for  an  instant  partakes  of  the  enormous  tem- 
perature, and  on  leaving  the  arc  is  cooled  as  quickly  as  pos- 
sible. In  the  arc,  the  combination  of  nitrogen  and  oxygen 
is  effected  to  a  certain  extent,  and  the  mixture  is  cooled  so 
suddenly  that  it  does  not  find  time  to  disunite.  The  nitro- 
gen oxides  thus  obtained  are  drawn  through  water,  and 
this  solution  of  nitric  acid  is  run  upon  soda,  to  produce 
sodium  nitrate,  or  on  lime  to  produce  calcium  nitrate,  the 
latter  called  nitro-lime  or  "Norwegian  saltpeter/'  These 
salts  entirely  replace  the  South  American  natural  salt. 

The  materials  used  in  this  industry  are  air  and  lime,  and 
to  these  is  added  electrical  energy.  Air  is  universal,  lime 
cheap  almost  everywhere,  and  electrical  energy  is  cheapest 
where  water  powers  are  most  abundant.  In  Norway,  water- 
power  can  be  developed  and  electrical  energy  supplied  from 
it  at  a  total  cost  of  $4.00  to  $8.00  per  horse-power-year. 
Some  other  countries  can  do  nearly  as  well.  Under  these 
conditions,  almost  every  country  can  afford  to  make  its 
own  nitrates,  and  so  be  independent  of  other  countries  for 
the  fertilizer  needed  in  peace  and  the  gunpowder  used  in 
war.  Norway  felicitates  itself  already  on  being  thus  in- 
dependent; nearly  200,000  horse-power  is  being  utilized 
there  by  a  $15,000,000  syndicate,  and  the  industry  is  spread- 
ing rapidly  over  Europe.  The  study  of  this  problem,  its 
solution,  and  the  rapid  development  of  this  vigorous  in- 
dustry, is  one  of  the  most  remarkable  chapters  in  the  history 
of  recent  industrial  development.  In  this  accomplishment, 
electrochemistry  has  signally  aided  the  agriculturist,  and 
demonstrably  multiplied  the  food-supply  resources  of  all 
civilized  and  highly-populated  countries. 

Boron  is  an  element  which  has  until  recently  defied  the 
best  efforts  of  chemists  to  isolate  in  a  pure  state.  It  is  an 
element  which  may  have  important  application  in  the 
manufacture  of  a  high-class  special  steel— boron  steel.  Dr. 
Weintraub,  one  of  our  fellow  members,  has  recently  solved 


158  MODERN  SCIENCE  READER 

the  problem  of  its  production  by  an  adaptation  of  the 
"oxygen-nitrogen"  arc  apparatus,  and  utilizing  the  same 
principle  of  introducing  the  material  into  the  arc  and  very 
rapidly  cooling  the  products  obtained.  We  mention  this 
not  because  of  its  great  commercial  importance  at  present, 
but  because  it  shows  how  the  "arc  method"  may  be  of 
wide  application  in  solving  other  difficult  chemical  prob- 
lems; it  has  opened  before  us  a  new  method  in  chemical 
science,  and  may  give  birth  to  many  and  various  new 
chemical  industries. 

///. .  Electric  Furnaces 

Electric  furnaces  are  furnaces  in  which  the  necessary 
heat  or  degree  of  temperature  is  produced  or  attained  by 
means  of  electrical  energy.  The  electric  current  is  used  in 
these  furnaces  solely  for  its  heating  or  thermal  effect,  and 
either  alternating  or  direct  current  may  be  used,  but  alter- 
nating is  preferred  because  of  its  easier  generation  and 
management,  capability  of  being  procured  from  transform- 
ers, and  absence  of  electrolytic  effects. 

Electric  furnaces  render  remarkable  and  highly  valuable 
service  to  the  chemist  and  metallurgist,  for  two  distinct 
and  unique  capabilities;  they  can  generate  heat  within 
themselves  without  the  use  of  combustion  and  the  conse- 
quent products  of  combustion  to  complicate  the  working 
of  the  furnace,  and  they  can  besides,  if  desirable,  produce 
temperatures  absolutely  unapproachable  in  furnaces  using 
fuel,  and  thereby  enable  the  carrying  out  of  operations 
only  possible  at  these  extremely  high  temperatures.  The 
upper  limit  of  electric  furnace  temperature  is  simply  the 
volatilizing  point  of  carbon,  the  temperature  at  which  the 
material  of  which  the  lining  of  the  furnace  is  made  is 
boiled  away.  This  is  about  3,700°  C.  or  6,692°  P.  The 
simple  statement  that  this  is  three  times  as  high  as  the 
melting  point  of  cast  iron  may  give  some  notion  of  the 
enormous  temperature  here  at  one's  command.  Besides 
high  temperature,  the  efficiency  of  application  of  electrical 


ELECTROCHEMISTRY  159 

heat  to  the  useful  purpose  is  usually  high;  in  many  cases 
50  to  75  per  cent,  of  all  the  heat  developed  can  be  usefully 
applied,  as  against  5  to  50  per  cent,  utilized  in  fuel-fired 
furnaces.  The  heating  value  or  thermal  equivalent  of  the 
electric  current  is  perfectly  definitely  known;  one  kilo- 
watt-hour will  furnish  860  calories  (3,400  B.t.u.),  which  if 
applied  usefully  at  100  per  cent,  efficiency  would  bring  to 
boiling  and  convert  into  steam  1.35  kilograms  (3  pounds) 
of  water,  or  bring  to  melting  and  melt  about  3  kilograms 
(6.6  pounds)  of  cast  iron,  or  2.5  kilograms  (5.5  pounds) 
of  steel. 

Artificial  graphite  is  a  product  particularly  electro- 
chemical in  its  manufacture.  Your  fellow-townsman,  Dr. 
E.  G.  Acheson,  has  practically  created  this  industry  and 
his  name  sticks  to  the  product— Acheson  graphite.  No 
temperature  but  that  of  the  electric  furnace  can  convert 
the  ordinary  amorphous  carbon,  containing  small  amounts 
of  foreign  substances,  into  pure,  soft,  homogeneous,  unc- 
tuous graphite.  The  purity  of  the  product  and  its  quality 
has  even  surpassed  the  artifice  of  Mother  Nature  herself. 
Whereas  before  graphite  in  small  scales  was  laboriously 
gathered  from  Ceylon  and  Siberia,  and  with  great  pains 
worked  up  into  graphite  articles,  now  the  articles  are  simply 
molded  in  ordinary  impure  amorphous  carbon,  and  con- 
verted through  and  through,  retaining  their  shape,  into 
finished  and  complete  graphite  articles.  What  this  highly 
pure  product  is  going  to  do  for  lubrication,  for  annihilating 
the  friction  of  the  world's  machinery,  perhaps  only  a  few 
suspect  and  only  Mr.  Acheson  knows.  You  will  all  know 
more  about  this  soon,  and  every  one  of  you  who  uses  ma- 
chinery will  profit  by  it.  Meanwhile,  in  another  direction, 
probably  half  the  electrochemical  industries  now  operating 
are  beneficiaries  of  this  invention,  using  artificial  graphite 
anodes  in  electrolytic  operations  or  as  electrodes  in  electric 
furnaces.  The  electrochemical  industry  in  general  has 
been  most  wonderfully  helped  by  this  one  electrochemical 
process. 


160  MODERN  SCIENCE  READER 

Carborundum  stands  for  a  large  industry,  centered  at 
Niagara  Falls,  and  founded  also  by  Mr.  Acheson.  Twenty 
years  ago  the  name  was  not  in  the  dictionary ;  now  it  is 
known  all  over  the  world  as  the  most  efficient  abrasive  ma- 
terial in  use.  First  produced  just  across  the  Monongahela, 
in  a  little  furnace  as  large  as  a  cigar  box,  and  sold  for 
polishing  diamonds  at  many  dollars  per  ounce,  it  is  now 
made  by  tons  in  electric  furnaces  of  2,000  horse-power 
capacity,  and  competes  successfully  with  such  common 
natural  abrasives  as  emery  and  common  sand.  And  in 
fact,  common  silica  sand,  the  most  abundant  material  on 
earth,  with  common  carbon,  like  coke,  furnish  all  the  in- 
gredients necessary  for  the  furnace  to  work  upon  to  pro- 
duce SiC,  silicon  carbide.  Mr.  Acheson  not  merely  founded 
another  new  industry,  but  he  discovered  a  new  chemical 
compound;  he  has  enriched  science,  promoted  industry, 
and  created  new  instruments  of  service ;  no  wonder  that  his 
scientific  friends  have  showered  on  him  honors — the  Rum- 
ford  Medal,  the  Perkin  Medal,  and  two  years  ago  the 
presidency  of  this  Electrochemical  Society. 

Silicon  is  the  metal  whose  oxide  is  silica  or  sand  and  is 
by  far  the  most  abundant  metallic  element  on  earth.  Up 
until  very  recently  it  was  to  be  seen  only  in  chemical 
museums,  costly  and  useless — a  chemical  curiosity.  Now 
Mr.  F.  J.  Tone,  one  of  Mr.  Acheson 's  former  lieutenants, 
is  producing  it  by  the  ton  and  selling  it  by  the  carload,  at 
a  few  cents  per  pound.  The  chemical  world  has  found 
uses  for  it,  large  uses,  such  as  in  solidifying  steel,  making 
good  copper  castings,  reducing  other  metals  from  their 
oxides,  chemical  "pots  and  pans,"  etc.  This  illustrates 
again  the  variety  of  the  achievements  of  electrochemistry. 
Here  is%a  new  material  furnished  the  world  at  a  low  price 
and  all  sorts  of  workers  are  finding  all  sorts  of  advan- 
tageous uses  for  it.  The  electric  furnace  makes  it  from 
simply  sand  and  carbon,  with  electric  energy,  and  plus 
considerable  "brains." 

Calcium  carbide  is  the  product  of  another  American  in- 


ELECTROCHEMISTRY  161 

vention.  The  name  was  scarcely  in  chemical  books,  and 
the  purveyors  of  the  rarest  chemicals  did  not  have  it  on 
their  lists,  when  Mr.  Thomas  Wilson,  trying  to  make  some- 
thing else  in  the  electric  furnace,  made  this  compound  from 
ordinary  lime  and  carbon,  and  started  an  electrochemical 
industry  which  has  spread  all  over  the  civilized  world.  I 
am  almost  tempted  to  say  that  there  is  a,  calcium  carbide 
works  everywhere,  but  that  would  really  be  an  exaggera- 
tion, and  I  will  not  say  it.  The  best  thing  about  calcium 
carbide  is  that  it  is  easy  to  make ;  the  raw  materials  may  be 
found  almost  everywhere,  and  wherever  power  is  cheap  a 
flourishing  calcium  carbide  industry  may  be  built  up.  The 
curious  thing  about  it  is  that  its  chief  use  is  based  on 
destroying  it,  acting  upon  it  by  water  and  forming  acety- 
lene gas.  How  great  a  boon  acetylene  gas  has  been  to  the 
bicyclist,  automobilist,  for  lighting  trains,  isolated  houses, 
stations,  and  towns,  needs  no  recital  before  this  audience; 
but  the  value  of  acetylene  as  a  means  of  welding  with  the 
blowpipe  is  only  commencing  to  be  appreciated.  Acetylene 
welding  is  a  convenience  which  owes  its  existence  entirely 
to  the  electrochemical  production  of  calcium  carbide,  and 
the  iron  and  steel  and  other  metal  industries  are  being 
greatly  helped  by  its  use. 

Titanium  carbide  is  not  as  familiar  as  calcium  carbide. 
It  is  made  in  a  manner  similar  to  the  production  of  carbo- 
rundum, using  titanium  oxide,  (rutile)  and  carbon.  It  has 
no  uses  similar  to  calcium  carbide,  nor  any  like  silicon  car- 
bide. But  electrical  engineers  have  discovered  that  as  arc 
light  tips  or  electrodes  it  gives  the  most  efficient  arc  light 
yet  discovered,  with  a  light  efficiency  running  up  to  3 
candle-power  per  watt  of  electrical  energy.  This  is  prob- 
ably 50  per  cent,  of  the  theoretically  possible  conversion  of 
electrical  energy  into  light  energy,  and  is  doubly  as  efficient 
as  has  ever  before  been  attained.  What  this  means  for 
street  lighting  everywhere  is  difficult  to  realize;  perhaps 
the  best  and  most  easily  understood  comparison  is  to  say 
that  the  titanium  carbide  arc  lamp  is  to  the  ordinary  arc, 
11 


162  MODERN  SCIENCE  READER 

as  the  tungsten  filament  incandescent  lamp  is  to  the  carbon 
filament  lamp;  you  will  all  grasp  the  scope  of  that  state- 
ment. With  acetylene  lighting  on  one  hand,  and  titanium 
arc  lighting  on  the  other,  we  need  say  no  more  about  the 
influence  of  electrochemistry  on  modern  illumination. 

Phosphorus.  I  stated  before  that  the  potassium  chlorate 
on  safety  matches  was  all  being  made  electrochemically. 
We  can  say  practically  the  same  of  phosphorus.  The 
electric  furnace  enables  us  to  distill  phosphorus  much  more 
easily  and  safely  from  the  natural  phosphates,  than  the 
older  chemical  methods.  Calcium  carbide  gives  us  acety- 
lene gas,  and  another  electrochemical  furnace  gives  us  the 
phosphorus  to  "strike  the  light." 

Ferro-alloys  are  alloys  of  iron  with  the  more  expensive 
metals,  used  in  manufacturing  steels  of  various  kinds. 
Ferro-manganese  is  used  in  practically  all  steel,  ferro- 
silicon  is  used  in  almost  all.  Ferro-chromium,  nickel, 
tungsten,  molybdenum,  boron,  uranium,  vanadium,  are 
some  of  the  alloys  used  to  make  the  special  alloy  steels,  such 
as  find  great  use  in  rapid  tool  steel,  automobile  axles, 
armor  plate,  gun  steel,  etc.  These  alloys  are  of  great  im- 
portance to  the  steel  industry,  and  are  made  almost  exclu- 
sively in  electric  furnaces.  The  industry  has  flourished 
most  in  countries  having  cheap  power,  such  as  among  the 
French  Alps,  and  the  importations  into  this  country  have 
been  on  a  large  scale.  Fortunately,  we  are  commencing  at 
Niagara  Falls,  in  Virginia,  and  in  Canada,  to  supply  our- 
selves with  these  necessities  of  the  steel  industry,  and  we 
may  look  forward  to  a  steady  and  large  domestic  develop- 
ment of  this  industry.  Within  a  few  miles  of  this  hall,  a 
small  electric  furnace  is  now  at  work  making  f erro-tungsten 
to  go  into  high-class,  expensive  steel.  Pittsburg  is  going 
to  take  its  share  in  the  running  of  this  particular  electro- 
metallurgical  industry. 

Pig  iron  would  seem  to  be  about  the  last  item  to  find  a 
place  in  an  address  upon  the  electrochemical  industries. 
But  the  truth  must  "out":  electric  furnace  pig  iron  is  now 


ELECTROCHEMISTRY  163 

being  made,  and  made  and  sold  at  a  profit.  We  will  hasten 
to  admit  that  the  furnaces  are  small,  that  they  are  in  Cali- 
fornia and  Sweden,  where  fuel  is  expensive  and  power  is 
cheap,  that  a  great  deal  of  money  has  been  sunk  in  bring- 
ing them  to  their  present  condition ;  but  after  all  has  been 
admitted,  the  fact  remains  that  electric-furnace  produc- 
tion of  pig  iron  is  not  a  chimera,  but  an  accomplished  fact. 
Pittsburg  has  been  able  to  boast  that  she  "could  manu- 
facture a  ton  of  pig  iron  and  put  it  down  anywhere  in  the 
world  cheaper  than  it  could  be  there  produced."  That 
may  be  still  true  of  the  kind  of  pig  iron  which  Pittsburg  is 
able  to  make,  but  there  are  grades  and  qualities  of  pig  iron 
(Swedish  charcoal  pig  iron,  for  instance)  which  are  still 
imported  into  this  country  and  sold  at  double  the  price  of 
our  domestic  pig  iron.  And,  in  the  country  where  that 
charcoal  pig  is  slowly,  laboriously  and  skilfully  made,  the 
electric  shaft  furnace  is  able  to  compete  with  the  charcoal 
blast  furnace  in  producing  this  high  quality  pig  iron.  Dr. 
Haanel,  of  the  Canadian  Department  of  Mines,  has  in  a 
recent  report  given  us  the  most  reliable  information  about 
the  running  of  this  furnace.  The  construction  is  peculiar, 
and  still  somewhat  experimental,  the  full  power  for  which 
the  furnace  was  designed  has  not  yet  been  available  for 
running  it,  the  workmen  are  new  to  their  tasks,  the  over- 
seers are  still  learning,  the  irregularities  in  the  running 
are  not  yet  all  overcome,  and  many  of  the  minor  details 
are  yet  being  adjusted.  The  furnace  is  still,  in  brief, 
decidedly  in  the  formative  or  experimental  stage.  Yet,  not- 
withstanding, Professor  Odelstjerna,  one  of  the  most  expert 
of  Swedish  metallurgists,  states  that  the  cost  of  production 
is  $1.50  per  ton  less  than  in  the  Swedish  blast  furnaces.  If 
that  is  true  now,  it  needs  little  gift  of  prophecy  to  figure 
out  at  least  $2.50  per  ton  saving  when  the  furnace  is 
properly  run.  Three  similar  furnaces  of  greater  capacity, 
2,500  kilowatts  each,  are  to  be  erected  in  Norway;  three 
similar  ones  are  to  be  put  up  at  Sault  Ste.  Marie,  Canada. 
These  are  only  the  forerunners  we  may  be  sure,  of  dozens 


164  MODERN  SCIENCE  HEADER 

or  perhaps  even  hundreds  which  will  be  built  and  operated 
within  the  lifetime  of  most  of  this  audience.  The  time  at 
our  disposal  forbids  me  describing  these  interesting  fur- 
naces ;  I  can  only  refer  to  Dr.  Haanel  's  interesting  reports 
and  to  the  transactions  of  this  society,  particularly  to  our 
volume  xv.  One  surmise  of  my  own  I  will,  however,  take 
time  to  mention :  I  have  predicted  that  this  electric  furnace 
pig  iron,  made  without  the  admittance  or  use  of  air  blast, 
will  be  far  superior  to  ordinary  pig  iron  for  conversion  into 
steel,  because  of  the  absence  of  oxygen  or,  particularly,  of 
nitrogen.  Time  will  test  this  prediction,  too. 

Electric  steel  is  at  present  a  topic  of  absorbing  interest 
and  great  potentialities.  It  was  primarily  a  competitor  of 
the  most  expensive  kind  of  steel— crucible  steel.  It  was 
first  made  commercially  in  1900,  by  Mr.  F.  A.  Kjellin  of 
Sweden,  by  melting  together  in  an  electric  furnace  the 
same  high-grade  materials  which  are  usually  melted  down 
in  crucibles  to  form  crucible  steel.  The  product  was  made 
equal  in  quality  to  crucible  steel,  it  was  produced  in  lots 
of  a  ton  or  more  at  a  melt,  of  very  satisfactory  uniformity, 
and  with  cheap  water-power  to  furnish  electricity  the  cost 
was  considerably  below  that  of  crucible  steel. 

The  steel  melting  pot  or  crucible  is  a  siliceous  vessel, 
holding  about  100  pounds  of  steel,  lasting  only  a  few  heats, 
and  lifted  in  and  out  of  the  furnace  by  manual  labor.  The 
consumption  of  fuel  to  get  the  required  melting  heat  is 
wickedly  wasteful;  not  over  five  per  cent,  of  the  heat- 
developing  power  of  the  fuel  used  is  efficiently  utilized  as 
heat  in  the  melted  steel,  and  the  actual  proportion  is  usually 
less  than  half  that  much.  The  cost  of  labor,  crucibles  and 
fuel  is  excessive,  and  to  this  must  be  added  the  high  cost 
of 'the  pure  material  which  must  be  used— practically  the 
purest  iron  which  can  be  made. 

The  electric  furnace  is  changing  all  this,  rapidly  in  con- 
tinental Europe,  slower  in  Sheffield,  and  still  slower  in 
America;  but  the  change  is  spreading  surely  and  inevit- 
ably. Real  crucible  steel  will  soon  be  a  thing  of  the  past, 


ELECTROCHEMISTRY  165 

supplanted  entirely  by  electric  furnace  steel  of  equal  qual- 
ity, made  and  sold  much  more  cheaply. 

The  electric  furnaces  used  are  of  almost  all  types.  The 
induction  furnace  was  developed  commercially  by  Kjellin 
in  Sweden,  improved,  enlarged  and  greatly  developed  by 
his  associates  in  Germany,  combined  with  the  Colby  pattern 
in  America,  and  still  further  modified  by  Hiorth  in  Nor- 
way. Thirty-six  of  these  furnaces,  the  maximum  capacity 
being  one  at  Krupp  's  works  at  Essen,  Sy2  tons  at  a  charge, 
are  now  built  or  building.  The  American  Electric  Furnace 
Company  is  organized  to  push  their  building  and  operation 
in  America.  The  arc  radiation  furnace  was  developed  by 
Major  Stassano,  an  Italian  artillery  officer.  It  melts  by 
heat  radiated  from  powerful  electric  arcs.  Several  of  these 
are  in  operation  in  Europe,  and  a  gentleman  managing  one 
of  the  large  American  steel  companies,  who  has  just  re- 
turned from  an  inspection  of  the  different  electric  steel 
furnaces  operating  in  Europe,  tells  me  that  he  considered 
the  Stassano  furnace  as  doing  the  best  work  all  around,  of 
all  the  furnaces  he  saw  in  operation.  I  have  seen  this  fur- 
nace operating  smoothly  and  regularly,  in  Turin,  produc- 
ing steel  for  castings  which  were  being  sold  in  competition 
with  open-hearth  and  Bessemer  steel  castings  in  the  open 
market.  The  single  arc  furnace  is  best  illustrated  by  the 
Girod  furnace  which  is  built  like  the  body  of  an  open- 
hearth  furnace  with  the  electric  current  entering  the  bath 
by  carbon  electrodes  suspended  above  it  and  springing  arcs 
to  it  while  the  current  leaves  the  bath  through  metallic 
conductors  passing  through  the  saucer-shaped  hearth  below 
the  level  of  the  metallic  surface.  These  furnaces  work 
with  great  regularity,  and  a  large  number  are  operating 
in  Europe  in  capacities  up  to  12  tons  each.  I  am  informed 
that  the  Krupp  works  at  Essen  has  just  contracted  to  put 
in  five  of  these  of  the  12-ton  size,  which  would  confirm 
statements  made  to  me  by  my  European  friends  that  this 
furnace  is  working  the  best  of  all  the  electric  steel  furnaces 
now  operating  in  Europe.  The  double  arc  furnace,  of 


166  MODERN  SCIENCE  READER 

which  the  Heroult  furnace  is  the  most  familiar  type,  works 
with  two  arcs  in  series,  the  current  entering  the  bath  and 
leaving  it  also  through  electrodes  suspended  above  it.  The 
general  style  is  that  of  an  open-hearth  furnace  with  elec- 
trodes passing  through  the  roof.  The  current  used  is 
roughly  100  kilowatts  per  ton  of  steel  capacity,  and  the 
largest  so  far  operated  is  15  tons.  A  three-ton  furnace  of 
this  type  was  seen  by  you  at  the  Firth-Stirling  Steel  Works 
at  Demmler,  yesterday,  producing  crucible-quality  steel. 
The  U.  S.  Steel  Corporation  has  acquired  licenses  to  operate 
the  Heroult  furnace,  and  has  already  two  15-ton  furnaces 
in  operation.  Without  doubt,  the  Heroult  furnace  is  at  the 
present  time  the  most  popular  and  successful  electric  steel 
furnace  in  the  United  States.  I  have  not  time  to  more  than 
name  the  Keller,  the  Hiorth,  the  Harmet,  the  Frick— all  of 
which  are  operating  at  this  present  moment,  in  Europe. 

There  are  other  ways  of  making  steel  than  the  crucible 
method.  Bessemer  steel  is  the  cheapest,  and  open-hearth 
steel  is  next  best.  These  two  varieties  grade  into  each  other 
in  quality,  but  between  open-hearth  and  crucible  steel  there 
is  an  enormous  gap  in  price  and  in  quality  which  is  destined 
to  be  bridged  over  by  intermediate  qualities  of  electric  steel, 
as  it  becomes  cheaper  and  is  manufactured  on  a  larger 
scale.  This  will  soon  become  one  of  the  large  uses  of  the 
electric  method,  occupying  a  field  peculiarly  its  own.  It 
will  enable  steel  manufacturers  to  supply  steel  better  than 
the  best  open-hearth  product  at  less  than  the  price  of 
crucible  steel.  I  need  not  enlarge  upon  the  advantages  of 
this  to  a  Pittsburg  audience. 

There  are  also  varieties  of  methods  of  manufacture  of 
steel,  aside  from  the  melting  together  of  highly  pure  ma- 
terials as  in  the  crucible  method,  which  are  equally  avail- 
able in  most  types  of  the  electric  furnace.  The  Bessemer 
converter  takes  liquid  pig  iron  as  it  comes  from  the  blast 
furnace  and  by  rapid  oxidation  by  air  blast  converts  it 
into  steel.  Mr.  Heroult  has  tried  to  combine  the  Bessemer 
converter  with  the  electric  furnace,  in  one  apparatus,  the 


ELECTROCHEMISTRY  167 

idea  being  to  first  oxidize  the  metal  by  air  blast  and  then 
to  finish  it  while  electric  current  supplied  the  necessary 
heat.  I  have  no  information  that  this  combination  furnace 
is  anywhere  in  successful  operation,  but  the  equivalent  of 
the  same  operation  performed  first  in  the  Bessemer  con- 
verter and  then  on  the  blown  metal  transferred  into  an 
electric  furnace  for  finishing,  is  already  in  regular  com- 
mercial operation  at  the  South  Chicago  Works  of  the  U.  S. 
Steel  Corporation.  I  have  had  the  privilege  and  pleasure, 
thanks  to  Mr.  Heroult,  of  studying  that  operation,  in  com- 
pany with  Mr.  Heroult  and  the  editor  of  Metallurgical  and 
Chemical  Engineering.  You  may  find  a  description  of  the 
process  in  the  April  number  of  that  journal,  so  I  wiU  not 
repeat  it  here— except  so  far  as  to  say  that  15  tons  of  the 
product  of  the  Bessemer  blow,  oxidized  to  the  extent  usual 
in  the  Bessemer  converter,  was  kept  melted  less  than  two 
hours  on  the  basic  hearth  of  the  electric  furnace,  treated 
with  two  different  slags  to  refine  it  from  phosphorus  and 
sulphur,  deoxidized  or  "dead-melted,"  and  then  poured 
into  ingots  of  steel  intended  for  axles.  The  steel  produced 
was  of  better  quality  than  the  usual  corresponding  open- 
hearth  metal,  and  was  produced  at  slightly  less  total  cost. 
This  combination  process  bids  fair  to  give  a  new  lease  of 
life  to  the  declining  Bessemer  steel  industry;  its  economic 
importance  is  evident. 

The  open-hearth  steel  furnace  is,  at  present,  the  most 
important  of  the  methods  of  manufacturing  steel— "ton- 
nage steel."  It  makes  steel  from  pig  iron  and  scrap  of 
proper  quality,  or  from  pig  iron  and  iron  ore  (mill-scale), 
or  from  pig,  scrap,  and  ore.  It  makes  its  best  steel  on 
silica  hearths  from  high  grade  material  low  in  sulphur  and 
phosphorus,  and  its  cheapest  steel  on  basic  hearths  from 
almost  anything.  The  electric  furnace  can  do  any  or  all 
of  these  things,  and,  as  a  general  proposition,  produce  bet- 
ter steel  from  given  materials  than  the  open-hearth  furnace. 
Under  what  circumstances  it  will  pay  to  use  the  electric 
furnace  instead  of  the  open-hearth  furnace  would  take  at 


168  MODERN  SCIENCE  READER 

least  one  lecture  to  discuss;  we  will  not  go  deeply  into  it 
here.  In  Europe,  countries  which  have  very  cheap  water- 
power,  around  $10  per  horse-power  year,  and  fuel  costing 
$4  to  $6  per  ton,  are  finding  the  electric  furnace  the 
cheaper;  with  power  costing  $20  and  coal  $5,  the  two  are 
about  on  equal  terms ;  in  Pittsburg,  with  power  at  $30  and 
coal  at  $1,  the  open-hearth  furnace  is  by  far  the  cheaper 
for  producing  such  steel  as  it  can  produce.  However,  even 
here,  the  combination  of  Bessemer  and  electric  furnace  is 
possibly  cheaper  than  the  all  open-hearth  process;  the  com- 
bination of  open-hearth  and  electric  furnace  process  is  quite 
possible  and  practicable,  to  produce  crucible-quality  steel 
on  a. large  (tonnage)  scale,  and  the  combination  of  the 
open-hearth  and  electric  furnace  into  one  furnace  is  not  only 
a  possible  combination,  but  is  actually  being  "tried-out." 

The  latter  idea  is  to  take  an  open-hearth  furnace,  and  to 
place  electrodes  in  the  roof.  The  furnace  is  run  as  an 
ordinary  open-hearth  furnace,  with  the  electrodes  with- 
drawn; and  at  the  close  of  the  open-hearth  heat,  gas  and 
air  are  shut  off  entirely,  the  electrodes  lowered  into  prox- 
imity to  the  bath,  and  the  heat  finished  as  an  electric  fur- 
nace heat.  The  idea  is  sound  and  practicable,  and  will 
result  in  the  production  of  better  steel  than  can  be  obtained 
from  any  open-hearth  furnace,  at  but  a  slight  advance  on 
the  cost  of  the  open-hearth  steel,  say,  $2  to  $3  per  ton. 

As  to  the  capacity  for  enlargement  of  electric  steel  fur- 
naces, they  started  out  to  duplicate  the  crucible  steel  pro- 
cess, producing  100  pounds  of  melted  steel  at  a  heat,  and 
in  eight  years  have  risen  to  15  tons  capacity.  In  Europe, 
an  electric  calcium  carbide  furnace  of  18,000  kilowatts, 
capable  of  producing  200  tons  of  carbide  daily,  is  in  prac- 
tical operation.  A  furnace  of  like  power  capacity  could 
be  built  to  make  steel,  and  would  be  a  200-ton  steel  furnace 
or  larger.  We  can  therefore  say  with  assurance,  that  with 
a  little  more  experience  and  experiment,  electrometal- 
lurgists  will  be  able  to  furnish  the  steel  maker  with  electric 
steel  furnaces  as  large  as  are  wanted— up  to  200  tons' 
capacity  if  desired. 


THE  YEAST  CELL  AND  ITS  LESSONS1 

BY    W.    STANLEY    SMITH 

IT  has  often  struck  me  that  the  debt  modern  science  owes 
to  that  simple  organism  we  call  the  yeast  cell  has,  perhaps, 
never  been  sufficiently  considered  by  the  majority  of  well- 
educated  mankind.  It  may  be  that  in  the  haste  and  turmoil 
of  industrial  life  many  details  of  considerable  fascination 
must  necessarily  escape  our  ken;  it  may  be,  alas!  that 
some  of  us  are  content  to  live  our  lives  among  phenomena 
of  which,  as  Sir  Oliver  Lodge  once  said,  "we  care  nothing 
and  know  less. ' '  Be  this  as  it  may,  I  venture  to  think  that 
an  odd  half-hour  spent  in  those  delightful  fields  of  thought 
which  envelop  yeast  and  its  simple  cellular  life  will  not 
prove  entirely  unpleasurable,  nor,  indeed,  without  some 
measure  of  intellectual  profit. 

I  do  not  purpose  to  delve  far  back  into  the  dusty  records 
of  time.  It  will  suffice  for  our  purpose  if  we  place  our- 
selves beside  the  old  Dutchman,  Van  Leeuwenhoeck,  and 
take  a  glance  through  the  early  microscope  of  1680.  In 
the  field  of  vision  many  globules  floating  in  a  fluid  will  be 
discerned;  and  these,  forsooth,  are  yeast  cells  seen  in  their 
naked  simplicity  for  the  first  time  by  mortal  eye.  It  was 
thus  found  that  brewers'  barm  possessed  a  definite  struc- 
ture, and  the  primitive  step  in  a  long  series  of  discoveries 
July  accomplished;  but  it  is  curious  to  reflect  that  150 
years  should  then  intervene  during  which  nothing  of  cap- 
ital importance  was  added  to  our  knowledge.  With  the 
advent  of  the  nineteenth  century,  however,  each  day 
brought  forth  its  measure  of  scientific  progress.  The  scene, 
indeed,  became  crowded;  men  flocked  hither  and  thither 

'Published  in  Knowledge  and  Scientific  News  and  reprinted  in 
Scientific  American  Supplement,  August  14,  1909. 


170  MODERN  SCIENCE  READER 

declaring  novel  facts  and  fancies,  and  a  veritable  whirlpool 
of  conflicting  statement  and  contending  argument  ensued. 
At  this  distance  of  time  the  multitude  grows  dim ;  but  cer- 
tain figures  stand  out,  and  are  conspicuous  among  their 
clamorous  fellows.  We  must  note  at  least  four  remarkable 
personages— by  name,  Schwann,  de  Latour,  Berzelius,  and 
Liebig.  The  labors  of  de  Latour  in  France  and  Schwann 
in  Germany  were  almost  simultaneously  crowned  with 
eventful  discovery.  Yeast,  they  announced  with  no  un- 
certain voice,  is  a  living,  breeding  entity,  and,  moreover, 
is  the  cause  of  the  fermentation  of  sugar.  All  this  hap- 
pened during  the  opening  year  of  the  Victorian  age,  and 
against  these  strange  utterances  many  a  voice  was  raised. 
Those  of  us  who  have  studied  the  history  and  progress  in 
the  fermentive  arts  will  easily  recall  some  of  the  wild  and 
fantastic  guesses  which  were  then  poured  forth ;  but  among 
much  intellectual  dross  there  rang  out  the  reasoned  opinions 
of  Berzelius,  the  Swede,  and  Liebig,  the  giant  of  his  time. 
Berzelius  had,  without  doubt,  as  early  as  1827,  and  with 
greater  certainty  in  1839,  regarded  fermentation  as  de- 
pendent upon  catalytic  force,  or,  as  he  called  it,  vis  occulta, 
and  Liebig,  whose  chemico-mechanical  theory  held  ground 
for  some  years,  is  best  interpreted  by  quoting  his  own 
words,  as  they  appear  in  the  classic  Chemistry  of  Agri- 
culture and  Physiology.  "In  the  metamorphosis  of 
sugar,"  says  he,  "the  elements  of  the  yeast,  by  contact  with 
which  its  fermentation  was  effected,  take  no  appreciable 
part  in  the  transformation  of  the  elements  of  the  sugar; 
for  in  the  products  resulting  from  the  action  we  find  no 
component  part  of  this  substance." 

Many  other  theories  echo  from  out  those  times— theories, 
for  the  most  part,  utterly  vanished  from  the  ken  of  prac- 
tical science.  Albeit  a  strange  value,  a  vague  sense  of 
prophecy  is  discernible  in  certain  of  these  long-forgotten 
figments  of  scientific  imagination.  For  instance,  one  might 
legitimately  recall  Mitscherlich,  with  his  notion  of  contact, 
much  akin  to  the  action  of  platinum  sponge,  or  Meissner, 


YEAST  CELL  AND  ITS  LESSONS  171 

with  his  purely  chemical  theory,  or,  yet  again,  the  strange 
forecast  of  Colin  and  Kaemtz,  who  deem  the  whole  matter 
wrapped  deep  in  the  mysteries  of  electricity.  Suffice  it 
we  have  chosen  enough  for  our  wants,  and  it  will  be  appar- 
ent how,  in  the  whirligig  of  time,  forgotten  lore  will  suffer 
resurrection.  In  the  history  of  science  instances  are, 
indeed,  not  wanting  in  which  old  theory  clothed  in  the  garb 
of  newly-found  facts  itself  lives  anew. 

The  learned  Gabriel  Schwann  was,  by  inclination,  a 
physiologist,  and  his  work  on  yeast  must  be  regarded  in 
the  light  of  experimental  means  to  an  ambitious  end.  He 
sought  in  the  cell  the  very  foundation  of  life.  "I  have 
been  unable,"  says  he,  "to  avoid  mentioning  fermentation, 
because  it  is  the  most  fully  and  exactly  known  operation 
of  cells,  and  represents  in  the  simplest  fashion  the  process 
which  is  repeated  by  every  cell  of  the  living  body."  Let 
us  place  these  words  side  by  side  with  those  uttered  but 
the  other  day  by  the  great  Verworr.  "It  is  the  cell  to 
which  the  consideration  of  every  bodily  function,  sooner 
or  later,  drives  us.  In  the  muscle-cell  lies  the  riddle  of  the 
heartbeat,  or  of  muscular  contraction;  in  the  epithelial- 
cell,  in  the  white  blood  cell,  lies  the  problem  of  the  absorp- 
tion of  food;  in  the  gland-cell  are  the  causes  of  secretion, 
and  the  secrets  of  the  mind  are  slumbering  in  the  ganglion- 
cell."  It  thus  appears  clear  that  the  simple  saccharomy- 
cete  is  typical,  even  as  Schwann  argued,  of  all  organized 
life.  But  it  is  not  a  mere  question  of  crude  morphology ; 
this,  indeed,  is  but  the  least  subtle  of  those  analogies  which 
the  study  of  a  yeast  cell  will  suggest.  As  we  gaze  through 
the  eyepiece  of  some  sufficient  microscope  or  better  still 
observe  the  seething  world  of  the  brewers'  fermenting  vat, 
we  may  be  tempted  to  ask  the  old,  old  question,  Whence 
and  Whither?  What  lies  behind  this  fierce  energy  of 
decomposition,  this  astounding  fecundity,  this  altogether 
absorbing  mystery  of  life?  These  are  the  problems  which 
men  of  science  have  set  themselves  to  solve,  and  already 
they  have  gone  far.  I  think  that  it  would  not  be  difficult 


172  MODERN  SCIENCE  READER 

to  refer  the  latest  opinions  of  biologists  to  the  direct  and 
logical  result  of  reasoning  which  was  primarily  suggested 
by  research  on  the  mechanism  of  the  yeast  cell.  "  Physi- 
ology's present  answer  to  the  old  question,"  says  a  recent 
writer,  "is,  very  simply,  life  is  a  series  of  fermentations." 
And,  if  it  be  urged  that  we  do  not  yet  know  what  is  fermen- 
tation, that  we  know  as  little  of  the  working  of  the  house- 
wife 's  barm,  or  the  brewer 's  malt,  as  of  the  life  itself,  there 
will  be  no  one  to  gainsay.  For,  curiously  enough,  they 
seem  one  and  the  same  thing. 

There  is  a  plate  let  in  above  the  doorway  of  a  house  at 
Dole,  in  the  Rue  des  Tanneurs,  on  which  is  inscribed  this 
simple  phrase :  "  Ici  est  ne  Louis  Pasteur,  le  27  Decembre, 
1822."  And,  while  I  may  unhesitatingly  say  that  few 
more  momentous  events  have  occurred  in  the  annals  of 
science,  I  am  tempted  to  add  that  Pasteur's  birth  was  of 
equal  moment  to  the  whole  of  humanity.  For  what  man- 
ner of  man  was  this  lowly-born  tanner's  son?  And  what 
was  the  outcome  of  his  labors?  Let  Lord  Lister  tell  us  in 
his  own  grateful  words.  He  said:  "Pasteur's  researches 
on  fermentation  have  thrown  a  powerful  beam  which  has 
lightened  the  baleful  darkness  of  surgery,  and  has  trans- 
formed the  treatment  of  wounds  from  a  matter  of  uncer- 
tain, and  too  often  disastrous,  empiricism  into  a  scientific 
art  of  sure  beneficence. ' '  Pasteur 's  life  has  been  laid  bare 
to  us  by  several  writers,  among  them  his  son-in-law  Bom- 
pas,  and,  in  a  clever  little  monograph,  by  Mrs.  Percy 
Frankland.  From  the  latter  work  we  gather  how  Pasteur, 
in  his  youth,  was  much  addicted  to  the  gentle  Waltonian 
art.  Indeed,  for  some  years  he  took  no  heed  whatever  of 
books  or  other  dry-as-dust  learning.  It  was  not  until  dire 
necessity  forced  him  that  fishing-rod,  paint-box,  and  other 
profitless  joys  were  forsaken,  and  our  student  at  the 
Sorbonne  discovered  his  God-given  gifts.  And  then  a  cer- 
tain old  woman  of  Arbois,  in  her  rural  wisdom,  made  this 
odd  remark:  "What  a  pity,"  said  she,  "that  Louis  should 
bury  himself  in  a  muck-heap  of  chemistry,  for  in  truth  he 


YEAST  CELL  AND  ITS  LESSONS  173 

would  some  day  have  succeeded  in  making  name  and  fame 
as  a  painter." 

It  is  a  legitimate  question  to  ask  why  Pasteur  happened 
to  take  up  the  study  of  fermentation.  The  answer  affords 
another  of  those  happy  chances  which  are  the  salt  of 
scientific  life.  As  a  crystallographer  he  was  bent  on  solv- 
ing those  old  problems  suggested  by  the  tartaric  acids.  He 
noticed  how  one  type  of  this  acid  deflects  the  beam  of  light 
to  the  right,  another  to  the  left.  Further,  he  chanced  to 
observe  that  certain  micro-organisms  exercise  a  selective 
action  when  sown  in  these  solutions— thriving  in  one,  pin- 
ing in  the  other.  Here  then  was  a  clue,  for  surely  the 
contents  of  the  cells  Schwann  had  declared  alive  must  con- 
trol such  dainty  selective  action.  What  followed  in  those 
fruitful  years  it  were  quite  needless  for  me  to  recapitulate. 
Liebig  and  his  molecular  oscillations  were  forgotten  by  all 
save  the  faithful  few,  and  for  forty  years  mankind  reveled 
in  the  thought  that  the  fermentation  of  sugar  was  indis- 
solubly  connected  with  the  life  action  of  a  living  organized 
structure.  Yet,  on  the  crucial  point,  Pasteur  was  in  error. 
It  must  not  be  forgotten,  however,  that  by  his  classical 
experiments  with  the  isomeric  tartaric  acids  Pasteur 
practically  laid  the  foundations  of  stereo-chemistry.  The 
development  of  this  fruitful  branch  of  learning  was,  neces- 
sarily, slow  at  first,  and  indeed,  it  was  not  until  1873  that 
much  headway  was  achieved.  In  that  year  Wislicenus 
pointed  out  the  deductions  of  his  work  on  lactic  acid,  and 
it  seemed  clear  to  men  of  science  that  the  difference  be- 
tween compounds  of  identical  structure  was  due  to  differ- 
ences in  the  " arrangement  in  space"  of  atoms  within  the 
molecule.  It  is  to  the  further  development  of  this  difficult 
subject,  at  the  hands  of  Le  Bel  and  van't  Hoff,  who  elabor- 
ated the  theory  of  the  asymmetric  carbon  atom,  that  we 
largely  owe  our  knowledge  of  the  carbohydrates. 

The  new  century  opened  with  new  ideas.  A  book  deal- 
ing with  experimental  research  on  alcoholic  fermentation, 
and  relating  the  results  of  laboratory  experiments  dating 


174  MODERN  SCIENCE  READER 

from  1896,  appeared  in  the  year  1903.  It  is  entitled  "Die 
Zymasegdrung:  Untersuchungen  uber  den  Inhalt  der  Hefe- 
zellen  und  die  biologische  Siete  des  Garungsproblems."  The 
authors'  names  are  Eduard  Buchner,  Hans  Buchner,  and 
Martin  Hahn ;  and  it  became  evident  something  noteworthy 
had  happened.  It  was  briefly  this:  Buchner,  unhampered 
by  any  prejudice  concerning  the  connection  of  vitality  with 
fermentation,  betook  him  to  see  what  was  really  inside  the 
yeast  cell.  Accordingly,  he  mixed  a  small  quantity  of 
barm  with  very  fine  sand,  and  he  then  subjected  the  whole 
to  enormous  pressure.  This  hard  quartz  crushed  the  little 
yeast  cells  to  merest  pulp,  and  therefrom  flowed  a  wonder- 
working fluid.  It  was  found  that  Buchner 's  liquor  effected 
exactly  the  same  fermentation  in  a  saccharine  solution  as 
did  yeast  itself.  This  research  of  Buchner 's  actually 
proved  what  was  long  ago  conjectured  by  Liebig,  Traube, 
Berthelot,  and  Hoppe-Seyler,  namely,  that  the  intra-molec- 
ular  transformation  of  sugar  into  alcohol  and  carbon 
dioxide  is  due  to  an  enzyme  secreted  within  the  yeast  cell. 
This  capital  demonstration  forms  a  fitting  climax  to  a 
long  series  of  speculations  on  collateral  fermentations.  We 
will  call  to  mind  the  main  results  achieved  by  toilers  in 
these  different  fields  of  research.  In  the  year  1841  two 
French  chemists,  Payen  and  Persoz,  succeeded  in  isolating 
from  germinating  barley  a  substance  which  seemed  to 
possess  an  unlimited  capacity  for  saccharifying  starch. 
They  called  this  substance  diastase.  Later  on,  in  1860,  we 
find  Berthelot  experimenting  with  yeast,  and  he  isolated 
the  substance  to  which  Bechamp,  in  1864,  gave  the  name 
zymase.  Thirty  years  after  Donath  changed  this  name  to 
invertin,  and  we  thus  clearly  have  species  of  chemical  sub- 
stances which,  when  abstracted  from  living  organisms,  are 
able  to  effect  certain  well-defined  fermentations.  Mean- 
while, it  has  been  shown  that  many  processes  of  higher  life 
appear  to  be  governed  by  these  soluble,  unorganized  fer- 
ments, or,  as  Kuhne,  in  1878,  proposed  to  call  them, 
enzymes.  Incidentally,  I  should  here  mention  that,  like 


YEAST  CELL  AND  ITS  LESSONS  175 

many  other  termini  technici  with,  which  we  are  familiar, 
these  expressions,  ferment,  diastase,  enzyme,  or  what-not, 
must  be  understood  historically;  just  as  logic,  metaphysic, 
analytic  organon,  etc.,  can  only  be  apprehended  and 
understood  historically.  In  1831  Leuchs  discovered  that 
saliva  possessed  the  property  of  saccharifying  starch,  and 
fourteen  years  after  Miahle  isolated  the  ferment,  and  called 
it  salivary  diastase,  a  name  far  preferable  to  that  bestowed 
upon  it  by  Berzelius,  but  which  remains  to  this  day,  I  mean 
ptyalin.  Then  followed  the  discovery  that  the  specific 
functions  of  the  stomach,  liver,  and  pancreas  were  each 
controlled  by  their  specific  ferments,  which  we  shall  recog- 
nize as  pepsin,  rennet,  and  ptyalin.  And  now,  as  the  result 
of  the  brilliant  young  Gabriel  Bertrand's  work,  we  are 
even  bid  to  associate  the  taking  up  of  oxygen  by  the  lungs 
with  the  necessary  presence  of  an  enzyme,  which  he  has 
called,  appropriately  enough,  oxydase. 

It  is  now  possible  to  discern  the  connection  of  Buchner's 
bold  experiment  with  all  this  more  purely  physiological 
work.  He  proved  that  the  phenomena  apparent  when 
yeast  is  added  to  the  brewers'  wort  are  identical  in  prin- 
ciple with  all  these  other  fermentive  actions,  and  all  the 
research  of  more  recent  years  tends  but  to  strengthen  one's 
opinion  that  the  most  important  functions  in  the  economy 
of  life  are  under  the  control  of  enzymes,  or,  in  other  words, 
partake  of  the  nature  of  fermentation.  Quite  recently  Dr. 
Harden  has  had  something  to  say  about  zymase.  His  me- 
moir is  illuminating,  and,  if  that  were  possible,  still  further 
opens  our  eyes  to  the  complexity  of  the  subject.  He  indi- 
cates the  presence  in  yeast  juice  of  "something"  of  an 
organic  nature  which  is  not  affected  at  boiling  tempera- 
tures, and  to  which  it  owes  its  power  of  converting  sugar 
into  alcohol  and  carbon  dioxide.  Should  this  nameless 
"something"  be  withdrawn  from  yeast  juice,  zymase  al- 
most loses  its  characteristic ;  but,  on  the  other  hand,  if  more 
be  added,  so  as  to  swell  the  normal  quantity,  the  action  of 
zymase  may  be  doubled  or  quadrupled  in  ratio  to  the  quan- 


176  MODERN  SCIENCE  READER 

tity  present.  We  touch  here  upon  the  difficult  problems 
connected  with  the  so-called  co-ferments,  and  we  are  clearly 
on  the  fringe  of  important  discoveries.  Indeed,  many 
facts  are  already  at  hand  which  only  want  of  space  com- 
pels us  to  withhold  for  the  purposes  of  the  present  article. 
Some  German  chemists,  Bredig  among  others,  have  been 
able  to  imitate  very  closely  certain  fermentations  by  means 
of  finely-divided  metals,  such  as  platinum  or  gold,  and 
these  curious  ferment-like  solutions  may  be  " poisoned," 
chloroformed,  or  killed  just  as  if  they  were  alive.  This  is 
all  extremely  odd,  and  most  perversely  mechanical;  but 
there  is  something  behind  these  phenomena  which  awaits 
correlation  with  vinous  fermentation.  Meanwhile,  about 
three  years  ago  the  Zeitschrift  filr  Physikalische  Chemie 
published  the  following  remarkable  research,  which  must 
furnish  us  with  all  the  evidence  we  have  leisure  to  adduce 
on  this  occasion :  In  the  course  of  his  paper  on  the  '  *  Influ- 
ence of  Metals  on  the  Hydrolysis  of  Cane  Sugar, ' '  R.  Von- 
dracek  draws  attention  to  the  fact  that  authorities  differ 
* '  as  to  the  effect  of  metals  on  the  well-known  slow  inversion 
of  saccharose  by  boiling  water, ' '  and  proves  experimentally 
that  strips  of  platinum  foil  do  not  appreciably  influence 
the  rate  of  inversion,  thus  confirming  the  results  obtained 
by  Lindet.  On  the  other  hand  saccharose  (cane-sugar)  is 
rapidly  inverted  by  boiling  water  in  the  presence  of  plati- 
num black.  Sugar  solutions  acquire  a  decidedly  acid  reac- 
tion by  heating  with  platinum  black  for  fifteen  minutes, 
and  the  filtrates  undergo  inversion  on  further  heating.  If 
after  inverting  a  sugar  solution  by  treatment  with  platinum 
black  for  eight  hours  the  powder  be  immediately  heated 
with  a  fresh  solution,  the  latter  developes  no  acidity,  and 
it  is  not  inverted  more  rapidly  than  by  water  alone,  but 
the  inverting  property  of  the  platinum  black  is  restored  by 
exposure  to  air.  Again,  platinum  black  which  has  been 
previously  deoxidized  by  treatment  with  ammonia,  has  no 
influence  on  the  rate  of  inversion  by  pure  water.  From 
these  data  it  is  concluded  that  the  inversion  by  platinum 


YEAST  CELL  AND  ITS  LESSONS  177 

black  is  due  to  the  oxygen  contained  in  it,  which  oxidizes 
a  part  of  the  saccharose  to  one  or  several  organic  acids,  and 
thus  supplies  hydrogen  ions  to  the  solution. 

But  fermentation  is  destructive.  The  ferment  of  yeast 
splits  up  sugar  into  alcohol  and  carbon  dioxide;  pepsin 
resolves  albuminous  foodstuffs  into  substances  of,  presum- 
ably, simple  molecular  composition,  and  so  all  through  the 
list  we  have  had  occasion  to  mention.  On  the  other  hand, 
side  by  side  with  this  incessant  destruction,  life  is  charac- 
terized by  incessant  construction.  These  form,  indeed, 
the  two  most  striking  and  essential  phenomena  of  the  life 
process;  the  destruction,  the  analysis,  is  death;  the  con- 
struction, the  synthesis,  is  life.  And  a  constructive  fer- 
ment appears,  from  our  knowledge  of  enzymes,  to  be  a 
plain  contradiction  in  terms.  However,  even  this  stumb- 
ling block  has  apparently  been  removed,  and  it  was  a 
young  Englishman,  Croft-Hill,  who  first  showed  us  that  a 
constructive  ferment  is  not  only  thinkable,  but  that  it 
actually  exists.  And  here  again  the  lesson  was  furnished 
by  a  yeast  cell.  In  the  month  of  June,  1899,  a  paper  was 
presented  by  Croft-Hill  to  the  Chemical  Society,  in  which 
it  was  shown  that  the  action  of  the  maltase  of  yeast  (which 
is  the  enzyme  charged  with  the  special  function  of  convert- 
ing the  sugar  maltose  into  the  simpler,  and  more  readily 
fermentable,  sugar  glucose)  on  maltose  is  hindered  by  the 
presence  of  glucose,  and  is  incomplete.  The  effects  are 
more  marked  the  stronger  the  solution  of  maltose.  If  the 
maltase  be  allowed  to  act  on  a  forty  per  cent,  solution  of 
glucose,  there  is  an  apparently  reversed  hydrolytic  action 
resulting  in  the  formation  of  fifteen  per  cent,  of  maltose, 
at  which  point  equilibrium  occurs.  The  same  equilibrium 
point  is  reached  whether  we  start  with  a  solution  of  maltose 
or  glucose,  so  that  the  action  is  clearly  a  reversible  one.  It 
has  often  struck  me  that  the  divergent  results  various 
chemists  have  achieved  in  the  study  of  the  decomposition  of 
starch  may,  perhaps,  in  some  measure  be  accounted  for  by 
the  action  of  constructive  enzymes,  or  rather,  one  would 
12 


178  MODERN  SCIENCE  READER 

be  safer  in  saying,  by  the  general  tendency,  under  defined 
conditions,  for  reversionary  processes  to  become  manifest. 
It  is  rather  more  than  twenty  years  ago  since  Dr.  Wohl 
noted  the  phenomena  of  inversion  and  reversion  in  connec- 
tion with  the  action  of  weak  acids  on  certain  complicated 
sugars. 

If  further  evidence  be  required  as  to  the  possibility  of 
what  I  have  named  constructive  ferments,  it  may  be  found 
in  Emmerling's  work,  which  I  mention  with  reserve,  on 
amygdaline.  Under  the  influence  of  one  enzyme,  emulsin, 
this  substance  is  split  up  into  sugar,  hydrocyanic  acid,  and 
the  essence  of  bitter  almonds.  But  it  is  said  that  another 
ferment,  maltase,  common  to  yeast,  will  join  these  decom- 
position products  together  again  to  form  the  original 
substance. 

On  one  very  particular  point,  that  is  to  say,  the  mole- 
cular construction  of  these  enzymes,  ferments,  or  diastases, 
the  world  of  science  is  almost  entirely  ignorant.  This  ques- 
tion forms  one  of  the  many  chemical  problems  of  the  hour, 
and  we  start  with  the  shallow  fact  that  they  contain  the 
simple  elements  found  in  charcoal,  air,  and  water.  Beyond 
this  we  know  next  to  nothing.  I  think,  however,  we  may 
console  ourselves  with  the  reflection  that  we  are  at  least  on 
the  eve  of  important  discoveries.  My  friend,  and  former 
" chief,"  Emil  Fischer,  of  Berlin,  having  vied  with  Nature 
herself  in  the  manufacture  of  sugars,  has  now  turned  his 
attention  to  proteid  substances.  The  intervening  gulf  has 
already  been  bridged,  inasmuch  as  Fischer  has  traced  tho 
connection  between  the  configuration  of  a  sugar  and  its 
behavior  toward  ferments.  This  is  the  famous  "Schloss 
und  Schlussel"  theory,  the  happy  analogy  of  "lock  and 
key."  It  is  our  every-day  experience  that  yeast  cells 
assimilate  more  easily  the  sugars  of  which  the  molecular 
configuration  closely  resembles  that  of  the  most  digestible 
of  all  carbohydrates,  namely,  glucose.  Many  of  the  arti- 
ficially produced  sugars,  as  for  example  the  al  doses,  gulose 
and  talose.  are  quite  indifferent  to  the  fermentive  efforts 


YEAST  CELL  AND  ITS  LESSONS  179 

of  yeast,  and  the  complicated  bi-  and  tri-saccharoses  are, 
for  the  most  part,  resolved  into  simpler  molecular  construc- 
tions before  suffering  the  usual  decomposition. 

There  is  a  fertile  field  of  inquiry  open  to  investigation 
as  to  whether  some  of  the  curious  by-blows  of  fermentive 
action  may  not  lead  to  further  discrimination  between  con- 
structive and  destructive  fermentation.  We  have  certainly 
arrived  at  a  point,  in  so  far  as  these  studies  are  concerned, 
which  bids  us  be  cheery  as  to  the  future,  for  the  modern 
man  of  science  has  far  outstripped  those  learned  forbears 
of  his  who,  to  use  Sir  Edward  Elgar's  lugubrious  simile, 
were  like  "  blind  men  in  a  churchyard  at  midnight,  trying 
to  read  epitaphs  in  a  forgotten  tongue."  Emil  Fischer's 
work  alone  has  inspired  that  able  chemist,  Dr.  M.  0. 
Forster,  in  saying,  "It  is  permissible  to  prophesy  that  his 
contemporary  researches  among  purine  derivatives  and 
synthetical  polypeptides  will  culminate  in  dramatic  results, 
as  they  have  the  character  of  a  reconnaissance  preceding 
an  attack  on  the  proteids,  which  chemists  anticipate  will 
share  the  fate  of  the  two  other  principal  food  materials- 
fats  and  sugars."  Dr.  Gustav  Mann,  of  Oxford,  in  his 
erudite  work  on  the  Chemistry  of  the  Albuminoids  (a  work 
based  on  Cohnheim's  treatise,  but  which  forms  a  much 
expanded  version  of  the  original)  strikes  the  student  on  its 
perusal  as  predicting  the  early  synthesis  of  an  enzyme. 
Indeed,  the  advances  chronicled  therein  are  potential  to  a 
singular  degree ;  but  it  is  not  yet  time  for  the  full  fruits  of 
those  hundred-fold  labors,  directed  primarily  to  the  eluci- 
dation of  yeast  and  fermentation,  to  fall  to  the  husband- 
man's sickle. 

It  has  only  been  possible  for  me  to  touch  upon  one  or  two 
of  the  manifold  thoughts  which  suggest  themselves  when 
one  watches  the  activity  of  yeast.  I  might  have  mentioned 
the  interest  which  was  aroused  by  the  publication  of  Dr. 
de  Backer's  volume,  Les  Ferments  Therapeutiques,  in  1896; 
wherein  it  is  noted  in  how  anxious  a  manner  the  yeast 
cell  will  swallow  up  certain  bacteria,  pathogenic  and  other- 


180  MODERN  SCIENCE  READER 

wise,  and  it  is  shown  how  subcutaneous  injections  of  yeast 
may  possibly  be  used  to  destroy  the  germs  of  many  dire 
diseases.  Again,  in  proof  of  the  medicinal  effects  these 
microscopical  cells  will  occasion,  I  might  have  quoted  the, 
perhaps  hypothetical,  story  of  the  Hertfordshire  farmer, 
who  went  home  late  one  night  and  drank  a  pint  of  yeast  in 
mistake  for  buttermilk.  He  arose  three  hours  earlier  next 
morning.  Indeed,  the  thoughts  which  crowd  around  these 
simple  cells  partake  of  a  character  almost  universal.  To 
yeast  we  owe  the  nation's  bread,  and  the  nation's  second 
necessity,  beer;  and  many  other  needful  liquors  are  ours 
through  the  medium  of  yeast.  So  wide  is  the  survey  that 
the  disjointed  reflections  I  have  ventured  to  place  before 
you  form  but  a  tithe  of  those  our  theme  might  legitimately 
evoke.  But  all  these  must  now  be  passed  over,  and  we 
will  conclude  with  one  modest  Faust  dream.  If  Croft-Hill 
is  right,  and  the  action  of  maltase  is  reversible ;  if  Emmer- 
ling's  discovery  that  one  ferment  may  undo  the  work  of 
another  be  a  true  interpretation  of  Nature,  then  might  we 
not  expect  the  same  reasoning  to  apply,  under  conditions 
yet  unknown,  to  those  ferments  which  convert  living  proto- 
plasm into  relatively  dead  fatty,  connective  cartilage  or 
bone  tissue?  Metchnikoff  has  declared  this  process  is  the 
invariable  symptom  of  advancing  years,  and  we  may  quite 
legitimately  ask  in  what  manner  this  apparent  discovery 
of  constructive  ferments  will  ultimately  affect  such  momen- 
tous problems. 


THE  CHEMICAL  KEGULATION  OF  THE 
PROCESSES  OF  THE  BODY1 

BY  WILLIAM  HENEY  HOWELL,  M.  D.  PH.  D. 

AT  the  time  of  Sir  Charles  Bell,  physiologists  were  begin- 
ning to  realize  the  great  importance  of  the  nervous  system 
as  a  mechanism  for  regulating  and  coordinating  the  varied 
activities  of  the  body.  To  use  his  own  expression,  "The 
knowledge  of  what  is  termed  the  economy  of  an  animal 
body  is  to  be  acquired  only  by  an  intimate  acquaintance 
with  the  distribution  and  uses  of  the  nerves."  Since  his 
time  experimental  investigations  in  physiology  and  clinical 
studies  upon  man  have  combined  to  accumulate  a  large 
fund  of  information  in  regard  to  the  regulations  and  cor- 
relations effected  through  nervous  reflexes.  No  one  can 
doubt  that  very  much  remains  to  be  accomplished  along 
these  same  lines,  but  in  recent  years  we  have  come  to  under- 
stand that  the  complex  of  activities  in  the  animal  body  is 
united  into  a  functional  harmony,  not  only  through  a 
reflex  control  exerted  by  the  nervous  system,  but  also  by 
means  of  a  chemical  regulation  effected  through  the  blood 
or  other  liquids  of  the  organism.  The  first  serious  realiza- 
tion of  the  importance  of  this  second  method  of  regulation 
came  with  the  development  of  our  knowledge  of  the  inter- 
nal secretions  during  the  last  decade  of  the  nineteenth  cen- 
tury. The  somewhat  meager  information  possessed  at  that 
time  in  regard  to  these  secretions  developed  in  the  fertile 
imagination  of  Brown-Sequard  to  a  great  generalization, 
according  to  which  every  tissue  of  the  body  in  the  course 

'Address  of  the  vice-president  and  chairman  of  Section  K — Physi- 
ology and  Experimental  Medicine,  American  Association  for  the 
Advancement  of  Science,  Boston,  December  28,  1909.  From  Science, 
January  21,  1910. 

181 


:  *  2  MODERN  SCIENCE  READER 

of  its  normal  metabolism  furnishes  material  to  the  blood 
that  is  of  importance  in  regulating  the  activities  of  other 
tissues.  This  idea  found  a  general  support  in  the  facto 
brought  to  light  in  relation  to  the  physiological  activities 
of  the  so-called  ductless  glands,  and  subsequently  in  the 
series  of  remarkable  discoveries  which  we  owe  to  the  new 
zeienee  of  immunology.  In  recent  years  it  has  been  re- 
ifated  in  attractive  form  by  Sehiefferdecker  in  his  theory 
of  the  symbiotic  relationship  of  the  tissues  of  the  body. 
According  to  this  author  we  may  conceive  that  among  the 
tissues  of  ft  single  organism  the  principle  of  a  struggle  for 
existence,  which  is  so  important  a*  regards  the  relations  of 
one  organism  to  another,  is  replaced  for  the  most  part  by 
a  kind  of  symbiosis,  such  that  the  products  of  metabolism 
in  one  tissue  serve  as  a  stimulus  to  the  activities  of  other 
fisfwg.  If  a  muscle  is  stimulated  to  greater  growth  by  an 
excess  of  functional  activity  the  substances  given  off  to  the 
blood  during  its  metabolism  act  favorably  upon  the  growth 
of  other  muscles  which  are  not  directly  concerned  in  the 
increased  work,  or  upon  the  connective  tissue  surrounding 
and  permeating  the  muscular  mass;  and  conversely,  the 
development  of  connective  tissue  from  any  cause  aids 
directly  by  its  secretions  or  excretions  in  the  growth  of  the 
muscle.  There  is  thus  established  ft  circulu*  benignug  by 
means  of  which  each  tissue  profits  from  the  functional 
activity  of  its  fellow  tissues.  From  many  sides  and  in 
many  ways  facts  have  been  accumulating  which  tend  to 
impress  the  general  truth  that  the  co-activity  of  the  organs 
and  tissues  may  be  controlled  through  chemical  changes  in 
tb<;  liquid  midia  of  the  body,  as  well  as  through  nerve  im- 
pulses, but  in  physiology  at  least  we  owe  the  definite  formu- 
lation of  this  point  of  view  to  Bayliss  and  Starling, 
Through  their  investigations  upon  secretin  they  obtained 
an  explicit  example  of  how  one  organ  controls  the  activity 
of  another  organ  by  means  of  a  specific  chemical  substance 
given  off  to  the  blood  Other  facts  known  in  physiology 
fa  refUfd  to  HM  internal  itcretfofu  were  easily  brought,  into 


ACTIVATORS,  KIN  \-    -    \\        .      /      \  .  > 

with  this  definite  instance  furnished  by  the  secretin, 
aval  Starling's  convenient  term  of  "hormone,"  as  a  general 
designation  for  such  substances,  has  served  to  give  a  wide 

•.ley  to  the  conception.  The  word  and  the  generaliza- 
tion implied  by  it  have  been  adopted  by  investigators  in 
many  fields  of  biological  research  to  explain  phenomena  of 
correlation  which  heretofore  it  has  been  impossible  to 
bring  under  the  general  rubric  of  nervous  reflexes;  phe- 
nomena which  iu  fact  it  has  been  difficult  to  express  clearly 
in  any  precise  way  such  as  might  serve  to  stimulate  direct 
experimental  investigation.  An  interesting  example  of 
this  application  of  the  term  and  the  idea  contained  iu  it  is 
found  in  the  theory  advanced  by  Cunningham  to  explain 
the  development  and  inheritance  of  secondary  sexual  char- 
acteristics. This  author  constructs  *  system  of  hypothe- 
tical hormones  which,  if  present,  would  account  not  only 
for  the  development  of  the  secondary  sexual  characters, 
as  the  result  of  the  actiou  of  specific  hormones  furnished  by 
the  reproductive  cells,  but  would  also  make  conceivable  a 
met  hod  by  which  these  secondary  characters,  like  other 
somato^cnic  characters,  mi^ht  aft'evt  the  germ  cells  in  turn 
in  snch  a  definite  way  as  to  be  transmitted  to  the  following 
ireneratioiis  1:  j|  not  my  purpose  to  criticue  this  or  similar 
J  will  doubt  less  SWYC  *  good  purpose  in 
stimulating  and  directing  inves  It  does,  however, 

seem  probable  that  the  term  hormone,  like  some  ot'  the  use- 
ful terminology  of  immunology,  will  be  overworked,  and 
that  investigators  may  deceive  themselves  as  well  as  others 
when  they  conclude  :  \  Driven  relationship  is  au  e\ 

ample  of  hoi-  -illation.     It  has  occurred  to  me  that 

it  may  be  useful  in  connection  with  this  symposium  upon 
the  internal  secretions  to  review  very  brieily  the  state  of 

our  knowledge  in  regard  to  the  hormones,  with  the  purpose 

of  discussing  somewhat  the  probable  nature  of  their  action 
and  the  extent  of  their  distrihur. 

In  treating  this  subject   one  must  consider  also  the  more 
or   less  nearly    related    instances  of  combined   activity   of  a 


184  MODERN  SCIENCE  EEADER 

chemical  sort  which  are  expressed  by  such  terms  as  chem- 
ical activators,  kinases  and  co-ferments.  These  terms,  like 
that  of  hormone,  are  relatively  new,  they  have  been 
brought  into  existence  by  investigators  to  explain  or  to 
express  special  reactions  connected  with  metabolism  and 
particularly  with  the  action  of  ferments.  Their  precise 
meaning  must  be  determined  by  further  knowledge  of  the 
facts  they  are  intended  to  describe,  but  something  may  be 
gained  by  attempting  to  define  them  as  they  are  used  in 
physiology  at  present.  The  word  activator  has  reference 
to  the  fact  long  known  that  the  ferments,  or  some  of  them 
at  least,  are  secreted  in  an  inactive  form,  a  preferment, 
which  is  activated  or  converted  to  an  active  form  by  a 
reaction  with  some  definite  substance  produced  elsewhere 
in  the  body.  Pepsin,  for  example,  is  secreted  as  pepsinogen 
and  is  activated  to  pepsin  by  the  hydrochloric  acid  formed 
by  other  gland  cells.  Calcium  salts  are  necessary  for  the 
activation  of  the  prothrombin,  and  enterokinase  or  calcium 
plays  a  similar  role  with  reference  to  the  trypsinogen.  It 
is  to  be  noted  that  reactions  of  this  kind  are  not  confined 
to  the  ferments.  The  typical  hormone,  secretin,  exists  in 
the  form  of  an  insoluble  prosecretin  which  may  be  activated 
by  acids,  and,  according  to  Delezenne,  calcium  takes  an 
essential  part  in  the  activation  of  enterokinase,  in  some- 
what the  same  way  as  occurs  with  thrombin.  The  nature 
of  these  activating  reactions  is  not  known.  The  view  has 
been  proposed  that  the  inorganic  constituents  involved, 
the  hydrochloric  acid  and  the  calcium  for  example,  act  as 
catalyzers  which  accelerate  a  reaction  that  would  occur 
without  their  assistance.  There  is,  however,  no  evidence 
to  show  that  thrombin  is  formed  in  any  amount  in  the 
absence  of  calcium  salts,  nor  that  pepsinogen  yields  pepsin 
without  the  presence  of  acids.  As  Bayliss  has  pointed  out, 
these  reactions  belong  to  the  irreversible  group,  and  it  is 
possible  that  the  activator  or  one  of  its  constituents  is 
represented  in  the  composition  of  the  active  substance  that 
is  formed.  However  that  may  be,  it  is  to  be  noted  that  the 


ACTIVATORS,  KINASES  AND  HORMONES     185 

process  of  activation  is  an  instance  of  chemiccl  coordina- 
tion. The  pepsin  formed  in  one  kind  of  gland  cell  is  acti- 
vated by  the  acid  produced  in  a  different  variety  of  cell. 
The  hydrochloric  acid  produced  in  the  stomach  is  carried 
into  the  intestin  with  the  flow  of  chyme  and  there  activates 
the  prosecretin  of  the  intestinal  epithelium  either  directly 
or  indirectly.  One  tissue,  in  other  words,  through  its 
products  of  metabolism  aids  another  tissue  in  the  perform- 
ance of  its  functional  duties. 

The  term  kinase  is  used  at  present  in  animal  physiology 
in  connection  with  two  reactions  only.  In  both  cases  it 
refers  to  an  activating  process  similar  to  those  just  con- 
sidered, except  that  the  activator  is  a  colloidal  substance 
of  unknown  composition.  The  pancreatic  juice  poured 
into  the  duodenum  contains  its  proteolytic  enzyme  in  the 
form  of  a  trypsinogen  which  is  activated  immediately  by 
trypsin  by  contact  with  the  duodenal  epithelium  or  with 
the  secretion  furnished  by  this  epithelium.  The  activating 
substance  is  designated  as  enterokinase.  It  is  present 
normally  in  the  intestinal  juice  formed  in  this  part  of 
the  alimentary  canal,  or  it  may  be  obtained  in  extracts 
of  the  mucous  membrane  of  the  duodenum  or  jejunum. 
According  to  Pawlow,  however,  the  intestinal  secretion  ob- 
tained by  direct  mechanical  stimulation  of  the  epithelium 
is  lacking  in  enterokinase.  This  latter  substance  is  pro- 
duced in  fact  only  under  the  influence  of  some  constituent 
of  the  pancreatic  juice,  possibly  the  trypsinogen  itself.  In 
other  words,  it  would  seem  that  the  enterokinase  must  itself 
be  activated  before  it  can  fulfil  its  functions  as  an  activator 
of  the  trypsinogen.  The  chain  of  inter-related  processes 
occurring  at  this  point  in  the  act  of  digestion  becomes 
somewhat  intricate,  as  follows :  Hydrochloric  acid  formed 
in  the  stomach  and  brought  into  the  intestin  with  the 
chyme  stimulates  the  epithelial  cells  of  the  intestin  to 
form  secretin  and  to  pass  it  into  the  blood.  The  secretin 
conveyed  by  the  blood  to  the  pancreas  stimulates  this  organ 
to  secrete  pancreatic  juice.  The  pancreatic  juice  is  carried 


186  MODERN  SCIENCE  KEADEK 

to  the  duodenum  and  stimulates  the  epithelial  cells  to  form 
enterokinase  which  then  activates  the  trypsinogen  to  tryp- 
sin.  Assuming  that  all  of  these  steps  are  verified  by  future 
work,  we  have  in  this  series  of  events  an  excellent  example 
of  chemical  coordination,  that  is  to  say,  of  coordination 
effected  by  chemical  stimuli  conveyed  from  one  organ  to 
another  through  the  liquids  of  the  body.  It  may  be  noted 
in  passing  that  the  epithelial  cells  of  the  duodenum  under 
the  influence  of  acids  or  soaps  form  an  internal  secretion, 
the  secretin,  while  under  the  influence  of  the  pancreatic 
juice  they  produce  an  external  secretion,  the  enterokinase. 
It  is  of  course  possible  that  these  two  different  functions 
are  subserved  by  separate  cells,  but  so  far  as  our  evidence 
goes  at  present  we  must  infer  rather  that  one  and  the  same 
epithelial  cell  gives  either  an  internal  or  an  external  secre- 
tion according  to  the  nature  of  the  chemical  stimulus  acting 
upon  it.  While  there  can  be  no  doubt  at  all  of  the  existence 
of  enterokinase  and  of  its  wonderful  effect  in  activating 
almost  instantaneously  the  trypsinogen  of  the  pancreatic 
juice,  much  uncertainty  prevails  as  to  its  nature  and  its 
mode  of  action.  Pawlow  thought  that  it  belongs  to  the 
group  of  enzymes,  and  this  view  has  been  supported  in  an 
almost  convincing  way  by  the  experiments  of  Bayliss  and 
Starling.  In  accordance  with  this  view  it  is  found  that 
the  substance  exhibits  a  certain  degree  of  thermolability, 
being  destroyed  at  a  temperature  of  67°  to  70°  C.,  although 
in  this  respect  it  is  less  sensitive  than  most  of  the  well- 
known  enzymes.  From  this  standpoint  the  action  of  the 
enterokinase  upon  the  trypsinogen  would  come  under  the 
general  head  of  catalytic  reactions,  but  here  again  it  is  to 
be  observed  that  its  action  differs  from  that  of  the  other 
enzymes  in  the  great  rapidity  with  which  it  is  completed, 
a  rapidity  quite  comparable  to  that  of  ordinary  chemical 
reactions.  Other  observers  (Dastre  and  Stassano,  Ham- 
burger and  Hekma,  Cohnheim)  have  contended  that  the 
enterokinase  unites  permanently  and  quantitatively  with 
the  trypsinogen,  after  the  manner  of  an  amboceptor  and 


ACTIVATORS,  KINASES  AND  HORMONES     187 

complement,  to  form  a  new  and  active  compound,  the  tryp- 
sin,  and  the  whole  reaction  has  been  still  further  compli- 
cated by  the  discovery  (Delezenne)  that  the  trypsinogen 
may  be  activated  by  calcium  salts  without  the  presence  of 
enterokinase.  The  action  of  the  calcium  requires  some 
time  for  its  development,  but  when  it  occurs  it  takes  place 
not  gradually,  but  abruptly,  just  as  in  the  case  of  the 
activation  produced  by  enterokinase.  The  further  fact 
stated  by  Delezenne  that  the  enterokinase  itself  needs  the 
presence  of  calcium  salts  before  it  acquires  the  property  of 
affecting  trypsinogen  suggests  naturally  the  thought  that 
the  action  of  the  enterokinase  may  be  at  bottom  another 
case  of  calcium  activation.  Pozerski  states  that  in  the  in- 
active pancreatic  juice  obtained  by  injections  of  secretin 
calcium  is  not  present;  whereas  in  the  active  juice  follow- 
ing upon  the  use  of  pilocarpin,  calcium  is  contained,  and 
the  digestive  action  of  the  juice  runs  parallel  with  the  con- 
tent in  calcium.  But  whether  the  enterokinase  acts  as  a 
ferment,  or  an  amboceptor,  or  a  calcium  carrier  it  consti- 
tutes a  special  type  of  organic  activator,  and  this  fact  sug- 
gests the  possibility  that  other  processes  in  the  body  may 
be  controlled  by  similar  compounds.  At  present  only  one 
other  organic  activator  of  this  kind  has  been  described, 
namely,  the  thrombokinase  of  blood  coagulation.  This 
hypothetical  substance  is  given  great  importance  in  the 
theory  of  coagulation  proposed  by  Morawitz.  According 
to  this  theory  the  blood  corpuscles  under  abnormal  environ- 
ment yield  an  unknown  substance  of  colloidal  nature  which, 
together  with  calcium,  is  necessary  for  the  complete  activa- 
tion of  thrombin,  and  therefore  for  the  clotting  of  blood. 
A  similar  kinase  is  furnished  by  the  tissues  in  general,  so 
that  blood  escaping  from  a  vessel  and  coming  in  contact 
with  the  surrounding  tissues  obtains  from  them  a  kinase 
which  accelerates  the  process  of  clotting.  The  evidence  for 
the  existence  of  this  kinase  is  far  less  satisfactory  than  in 
the  case  of  the  enterokinase,  indeed  one  may  have  serious 
doubts  whether  the  facts  at  present  warrant  the  assumption 


188  MODERN  SCIENCE  READER 

that  a  specific  organic  kinase  must  cooperate  with  the  cal- 
cium in  activating  the  thrombin,  but  if  the  idea  is  demon- 
strated to  be  correct  it  will  furnish  another  very  interesting 
example  of  the  way  in  which  chemical  coordination  may  be 
employed  in  the  body.  In  this  case  the  blood  may  be  sup- 
posed to  stimulate  the  tissue  cells  to  form  a  substance  not 
directly  of  importance  to  their  own  activity,  but  which  ini- 
tiates the  coagulation  of  the  blood,  stops  the  hemorrhage 
and  thus  saves  the  organism  from  destruction.  The  series 
of  events  is  quite  parallel  to  that  described  for  the  pan- 
creatic juice  and  the  enterokinase. 

In  addition  to  the  activators  of  the  inorganic  and  the 
colloidal  type  there  is  perhaps  a  third  kind  of  activation 
exemplified  in  the  substances  known  as  co-enzymes  or 
co-ferments.  This  term  may  be  used  to  define  that  kind  of 
cooperative  activity  between  an  enzyme  and  some  other 
noncolloidal  substance  which  we  see  illustrated  in  the 
influence  of  the  bile  salts  upon  pancreatic  lipase.  The 
process  differs  from  activation  of  a  preferment  to  a  fer- 
ment only  in  that  the  combination  of  the  enzyme  with  its 
activator  is  dissociable  instead  of  being  permanent.  By 
dialysis  or  otherwise  the  co-enzyme  can  be  separated  from 
the  enzyme  and  the  action  of  the  two  may  be  tested  sepa- 
rately or  in  combination.  Perhaps  this  species  of  activa- 
tion may  be  more  common  in  the  animal  body  than  we  have 
supposed.  Bierry  and  Giaja  have  shown  that  the  amylase 
of  pancreatic  juice  loses  its  diastatic  action  entirely  when 
dialyzed,  and  this  power  or  property  is  restored  upon  the 
addition  of  sodium  chloride.  It  would  seem  from  their 
experiments  that  the  amylase  is  active  only  when  combined 
with  an  acid  ion,  such  as  Cl  or  Br,  and  the  transition  from 
one  form  to  the  other,  from  the  active  to  the  inactive  or 
the  reverse,  is  easily  accomplished.  No  one  can  doubt  that 
all  these  forms  of  chemical  activation  are  allied  in  a  general 
way  to  the  more  interesting  and  obvious  mode  of  chemical 
coordination  illustrated  by  the  hormones.  Starling  defines 
hormones  as  chemical  messengers  which  formed  in  one  organ 


ACTIVATORS,  KINASES  AND  HORMONES     189 

travel  in  the  blood  stream  to  other  organs  of  the  body  and 
effect  correlation  between  the  activities  of  the  organ  of 
origin  and  the  organs  on  which  they  exert  their  specific 
effect.  Such  substances  belong  to  the  crystalloid  rather 
than  the  colloid  class;  they  therefore  are  thermostable  and 
do  not  act  as  antigens  when  injected  into  the  living  ani- 
mal. The  general  idea  of  this  definition  is  clear  and  most 
suggestive,  but  in  its  details  it  is  made  especially  to  suit 
the  case  of  secretion,  and  therefore  may  not  fit  so  well  for 
other  substances  of  like  physiological  value.  Conveyance 
through  the  blood  stream,  while  certainly  the  most  common 
occurrence  for  this  class  of  bodies,  ought  not  to  constitute 
an  essential  part  of  their  definition.  The  secretin  formed 
in  the  intestinal  epithelial  cell  is  conveyed  to  the  pancreas 
in  the  blood  and  brings  about  a  correlation  between  the 
activity  of  this  gland  and  that  of  the  duodenum,  but  on 
the  other  hand  some  substance  contained  in  the  pancreatic 
juice  and  conveyed  to  the  duodenum  in  the  stream  of  secre- 
tion excites  the  formation  of  the  enterokinase,  and  thus 
correlates  the  activity  of  the  duodenum  with  that  of  the 
pancreas.  The  two  actions  seem  to  be  so  similar,  except 
for  the  means  of  transport,  that  one  would  naturally  put 
them  in  the  same  class.  By  the  same  reasoning  we  might 
be  justified  in  designating  the  hydrochloric  acid  of  the 
gastric  juice  as  a  hormone  in  reference  to  its  action  in  caus- 
ing a  formation  of  secretin  in  the  epithelial  cells  of  the 
duodenum.  One  can  imagine  that  a  similar  transporta- 
tion may  occur  in  the  secretions  of  the  reproductive  or 
respiratory  passages,  in  the  cerebro-spinal  fluid,  as  seems 
to  be  the  case  for  a  time  at  least  with  the  secretion  of  the 
pars  intermedia  of  the  pituitary  gland,  or  even  along  the 
axial  stream  of  a  nerve  fiber.  If,  as  seems  to  me,  the  idea 
of  correlation  or  coordination  is  the  essential  point  rather 
than  the  assumption  that  the  product  must  constitute  an 
internal  secretion,  we  might  modify  the  definition  so  far 
as  to  designate  as  hormones  those  substances  in  solution 
which,  conveyed  from  one  organ  to  another  through  any  of 


190  MODERN  SCIENCE  READER 

the  liquid  media  of  the  body,  effect  a  correlation  between 
the  activities  of  the  organ  of  origin  and  the  organ  on 
which  they  exert  their  specific  effect.  As  regards  the 
nature  of  the  action  of  the  hormones  on  the  organ  affected 
we  know  too  little  to.  make  any  safe  generalization.  In  the 
case  of  the  secretin  it  seems  most  probable  that  the  hormone 
arouses  the  pancreatic  cells  to  an  act  of  secretion,  and  there- 
fore it  has  in  this  instance  the  value  of  a  chemical  stimulus. 
But  in  other  cases  the  effect  of  the  hormone  may  be  rather 
of  the  nature  of  an  activation.  This  at  least  would  seem 
to  be  true  for  the  hormone,  of  unknown  nature,  given  off  by 
the  pancreas  and  concerned  in  the  glycolysis  of  sugar  in  the 
organism.  The  effect  of  the  hormone  adrenalin  upon  the 
musculature  innervated  by  the  sympathetic  system  may 
also  be  of  the  nature  of  an  activation  rather  than  of  a 
chemical  stimulation. 

The  substances  of  known  composition  which  may  be  re- 
garded as  playing  the  role  of  hormones  are  few  in  number, 
three  or  four  at  most,  as  follows:  First,  the  carbon  dioxide 
formed  in  the  tissues,  particularly  in  muscle  during  con- 
traction. It  seems  agreed  now  that  the  carbon  dioxide 
acts  as  the  normal  stimulus  to  the  respiratory  center. 
When  produced  in  the  working  muscles  in  such  quantities 
as  to  raise  perceptibly  the  carbon  dioxide  tension  in  the 
alveoli  of  the  lungs  and  the  blood  of  the  pulmonary  veins, 
the  respiratory  center  is  excited  to  greater  activity  and 
the  excess  above  the  normal  contents  is  thereby  removed; 
second,  the  adrenalin  of  the  adrenal  glands  which  in  some 
way,  directly  or  indirectly,  makes  possible  the  full  func- 
tional activity  of  the  involuntary  musculature  of  the  body . 
third,  the  hydrochloric  acid  produced  in  the  stomach  which 
stimulates  the  formation  of  secretion  in  the  duodenal 
epithelium;  and  fourth,  possibly  the  iodothyrin  of  the 
thyroid  gland  with  its  dynamogenic  effect  upon  the  neuro- 
muscular  apparatus  of  the  body.  In  addition  there  are  a 
number  of  hormones  of  unknown  composition  which  have 
been  either  proved  or  assumed  to  exist,  and  which  are  held 


ACTIVATORS,  KINASES  AND  HORMONES     191 

responsible  for  certain  well-known  correlations  of  function : 
The  pancreatic  secretin  formed  in  the  epithelium  of  the 
duodenum  or  jejunum  which  stimulates  the  flow  of  pan- 
creatic secretion;  the  gastric  secretin  formed  iu  the  pyloric 
mucous  membrane  which  gives  rise  to  the  chemical  secretion 
of  gastric  juice ;  a  secretin  formed  in  the  duodenal  epithe- 
lium which  stimulates  the  formation  of  intestinal  juice  in 
the  following  segments  of  the  intestin ;  unknown  hormones 
of  pancreatic  origin  which  determine  the  absorption  activ- 
ity of  the  intestinal  epithelium;  vaso-dilator  hormones 
formed  in  tissues  in  functional  activity  and  which  have  a 
specific  effect  upon  the  vessels  of  the  functioning  organ; 
a  vaso-constricting  and  a  diuretic  hormone  formed  in  the 
posterior  lobe  of  the  pituitary  body ;  a  hormone  controlling 
the  growth  of  the  bones  and  connective  tissues  produced  in 
the  anterior  lobe  of  the  pituitary  body ;  a  hormone  control- 
ling the  oxidation  of  sugar  in  the  body  and  produced  in 
the  cells  of  the  islands  of  Langerhans  in  the  pancreas;  a 
hormone  produced  in  the  thymus  which  controls  possibly  in 
some  way  the  development  of  the  reproductive  organs;  a 
vaso-constricting  hormone  formed  in  the  kidneys;  a  hor- 
mone in  the  salivary  glands  which  controls  the  flow  of 
water  from  the  blood  capillaries  in  the  glands;  a  hormone 
produced  in  the  foetus  in  utero  which  stimulates  the  growth 
of  the  mammary  glands;  a  hormone  in  the  ovary  which 
controls  the  growth  of  the  uterus  and  the  processes  of 
menstruation;  a  hormone  in  the  ovary  which  controls  the 
implantation  of  the  fertilized  ovum  and  the  growth  of 
placental  tissue ;  a  hormone  in  the  testis  which  initiates  the 
development  of  the  secondary  sexual  characteristics  in  the 
male;  hormones  of  an  indefinite  number,  produced  in  all 
the  tissues  and  acting  specifically  upon  the  determinants 
in  the  gametes  in  such  a  way  as  to  make  possible  theitrans- 
mission  of  acquired  characteristics.  It  is  evident  from  this 
summary  that  there  is  a  well-developed  tendency  in 
physiology  at  the  present  day  to  utilize  the  conception  of 
hormones  to  explain  all  relationships  not  otherwise  intel- 


192  MODERN  SCIENCE  READER 

ligible.  A  few  years  ago  the  number  of  hypothetical  enzy- 
mes in  the  body  was  likely  to  be  increased  whenever  a  new 
research  in  metabolism  appeared,  now  the  drift  seems  to  be 
in  the  direction  of  manufacturing  new  hormones.  This 
natural  inclination  to  abuse  a  new  and  attractive  idea  will 
not  of  course  prejudice  us  against  the  great  importance  of 
the  suggestion  which  we  owe  to  Bayliss  and  Starling.  It 
is  to  be  hoped  only  that  no  one  will  be  tempted  to  give  to 
these  hypothetical  hormones  distinctive  names,  except  in 
cases  such  as  the  secretin,  adrenalin,  etc.,  in  which  the  sub- 
stances have  been  isolated  in  some  degree  of  purity.  For 
once  a  specific  name  has  become  attached  to  an  entirely 
unknown  substance,  it  acquires  henceforth  an  easy  currency 
in  our  literature,  and  soon  many  of  us  unconsciously  as- 
sume that  the  thing  so  designated  constitutes  one  of  the 
verified  facts  of  our  science.  By  way  of  example  one  may 
cite  the  thrombokinase  which  has  become  such  a  familiar 
term  in  the  literature  of  coagulation  and  which  not  infre- 
quently is  employed  by  writers  as  though  its  existence  were 
a  settled  fact. 

Among  his  other  valuable  suggestions  regarding  the 
characteristics  of  the  hormones,  Starling  has  called  atten- 
tion to  the  fact  that  some  of  them  act  by  increasing  the 
processes  of  disassimilation  or  catabolism,  while  others  ap- 
parently stimulate  the  processes  of  assimilation  or  growth. 
In  this  latter  group  we  may  include  the  hormones  of  the 
anterior  lobe  of  the  pituitary  body,  according  to  the  present 
conception  of  the  functions  of  that  gland,  and  all  of  the 
hormones  of  the  reproductive  cells.  These  latter  have  in 
general  what  has  been  designated  as  a  dynamogenic  action, 
they  cause  hypertrophies  in  various  organs  or  tissues  and 
invoke  therefore  processes  of  synthesis  rather  than  those  of 
splitting  and  oxidation.  Hypertrophy  as  an  outcome  of 
increased  functional  activity  is  a  familiar  phenomenon,  but 
as  Nussbaum  remarks,  the  hypertrophy  induced  by  testic- 
ular  or  ovarian  hormones  resembles  rather  the  effect  of  the 
growth  energy  exhibited  by  the  developing  embryo,  in  that 


ACTIVATORS,  KINASES  AND  HORMONES     193 

it  is  dependent  upon  influences  other  than  those  arising 
from  functional  use.     What  these  influences  may  be  is  at 
present  a  matter  of  pure  speculation.     In  his  recent  most 
interesting  contributions  to  our  knowledge  of  growth  Rub- 
ner  has  been  led  to  assume  that  the  property  of  growth  in 
the  young  organism  is  connected  with  certain  special  chem- 
ical  complexes    in   the    protoplasmic    material,    complexes 
which  have  nothing  directly  to  do  with  the  simple  main- 
tenance of  the  nutrition  of  the  cell  and  which  after  adult 
life  is  reached  disappear  for  the  most  part  from  the  general 
soma.     In  line  with  this  hypothesis  one  might  assume  that 
the  hormones  given  to  the  blood  by  the  reproductive  cells 
contain  such  complexes  which  when   anchored  in  certain 
tissues  lead  to  an  accelerated  growth.     Perhaps  the  clearest 
and  most  interesting  experiments  made  upon  the  reproduc- 
tive hormones  are  those  reported  by  Nussbaum.     He  chose 
for  his  experiments  the  males  of  Rana  fusca  whose  repro- 
ductive organs  go  through  a  cyclical  period  each  year.     At 
the  proper  period  the  preparation  for  the  mating  season 
shows  itself  in  the  hypertrophy  of  the  seminal  vesicles,  of 
the  thumb  pads,  and  of  certain  muscles  in  the  forearm.     If 
the  frog  is  castrated  these  hypertrophies  do  not  occur,  or 
if  they  have  begun  before  the  castration  is  performed  retro- 
gressive changes  take  place.     On  the  other  hand,  the  usual 
hypertrophy  of  the  nuptial  organs  can  be  initiated  in  a 
castrated  frog  if  pieces  of  the  testis  from  another  frog  are 
introduced  into  the  dorsal  lymph  sacs.     The  pieces  thus 
introduced  do  not  become  grafted  permanently,  but   are 
gradually  absorbed  and  the  growth  of  the  thumb  pads  and 
of  the  muscles  in  the  forearms  falls  off  after  this  absorption 
is  completed.    Nussbaum  believes  that  the  stimulating  effect 
of  the  testicular  hormones  is  not  exerted  directly  upon  the 
tissues  which  show  the  increased  growth,  but  rather  upon 
the  portions  of  the  central  nervous  system  which  innervate 
these  tissues.     This  belief  rests  upon  the  experimental  fact 
that  if  the  peripheral  nerves  going  to  the  glands  and  pa- 
pillae of  the  thumb  pads  are  severed  on  one  side  the  testic- 
13 


194  MODERN  SCIENCE  READER 

ular  hormone  affects  only  the  other  intact  side.  This 
experiment  and  the  conclusion  drawn  from  it  opens  up  the 
interesting  question  whether  perhaps  the  reproductive  hor- 
mones in  general  exert  their  effect  through  the  central  nerv 
ous  system.  This  has  not  been  the  usual  belief,  and  the 
experiments  of  Nussbaum  are  open  to  the  obvious  objection 
that  the  section  of  the  peripheral  nerves  may  have  induced 
certain  secondary  changes  in  metabolism  which  indirectly 
antagonized  the  action  of  the  testicular  hormone.  At 
present  these  experiments,  so  far  as  I  know,  have  not  been 
repeated  with  this  objection  in  mind,  and  it  is  somewhat 
gratuitous  to  criticize  the  author's  conclusions  until  further 
work  is  reported. 


THE  SCIENCE  OF  CHEMISTRY  AND 
ITS  DEVELOPMENT1 

THE  SCIENCE1 

CHEMISTRY  is  that  branch  of  Natural  Science  which  deals 
with  the  various  material  substances  that  are  capable  of 
existence,  with  their  relations  to  one  another,  and  with  the 
laws  governing  their  various  transformations. 

THE  NAME.  The  origin  of  the  word  chemistry  is  uncer- 
tain. Chemia  (or  Chemie)  is  the  old  name  of  Egypt,  and 
as  the  art  of  making  gold  and  silver  was  first  practised  in 
that  country,  the  science  of  chemia  may  have  meant  orig- 
inally "the  science  of  Egypt."  Later,  however,  at  the 
time  of  the  Alexandrian  alchemists,  the  word  was  used  to 
denote  some  substance ;  and  as,  on  the  one  hand,  the  word 
chemi  means  "black,"  and,  on  the  other  hand,  the  first 
step  in  the  transmutation  of  metals  is  known  to  have  been 
a  process  of  blackening,  we  conclude  chemia  may  have  at 
that  time  denoted  the  "philosopher's  stone"— i.e.,  the  sub- 
stance employed  in  the  process  of  blackening  the  metals. 
Similarly,  in  the  form  al-kimiyd,  the  term  is  used  also  by 
the  early  Arabic  writers  to  denote,  not  their  art,  but  the 
substance  employed  in  that  art.  With  them,  however,  the 
term  was  used  in  much  the  same  sense  as  the  word  al-iksir, 
and  this  suggests  another  possible  derivation.  The  word 
iksir  is  derived  from  the  Greek  xeros,  which  means  dry. 
Possibly,  then,  the  word  Jcimiyd  may  have  been  derived 
from  the  Greek  chymos,  which  means  liquid;  and  while  at 
one  time  both  iksir  and  kimiyd  were  used  to  denote  a  sub- 
stance, the  words  chymia  and  alchymy  gradually  came  to 

JTaken  from  The  New  International  Encyclopaedia,  vol.  iv,  page 
559.  Copyright  1902,  1904,  1905,  1906,  1907,  1909  by  Dodd,  Mead 
&  Co. 

195 


196  MODERN  SCIENCE  READER 

denote  the  art  in  which  that  substance  was  employed,  the 
substance  itself  (the  philosopher's  stone)  retaining  only 
the  name  al-iksir. 

THE  BRANCHES  OP  CHEMISTRY.  The  facts  of  chemistry 
have  been  grouped  in  a  variety  of  ways,  either  in  the  inter- 
ests of  research  or  according  to  their  usefulness  in  connec- 
tion with  kindred  sciences  or  with  the  arts— hence  such 
titles  as  Animal,  Vegetable,  Medical,  Astronomical,  Metal- 
lurgical Chemistry,  etc.,  which  in  a  general  way  explain 
themselves.  Chemistry  proper  may  be  considered  as  com- 
prising the  following  four  branches :  analytical,  descriptive, 
general  and  applied.  Analytical  chemistry  may  be  defined 
as  the  art  of  determining  the  composition  of  substances; 
under  the  names  of  technical  analysis,  physiological  anal- 
ysis, etc.,  many  of  its  methods  form  an  important  part  of 
applied  chemistry.  Descriptive  chemistry  deals  with  the 
chemical  and  physical  characteristics  of  substances;  it 
forms  a  record  of  the  properties  of  substances,  which  are 
arranged,  for  convenience  of  reference  or  for  didactic  pur- 
poses, in  accordance  with  the  principles  of  general  chem- 
istry. The  two  great  subdivisions  of  descriptive  chemistry 
are  inorganic  and  organic  chemistry;  the  latter  dealing 
with  the  compounds  of  carbon,  the  former  with  those  of  all 
the  other  elements.  General  chemistry  includes  theoretical 
and  physical  chemistry,  which  are  usually  treated  together. 
Theoretical  chemistry  comprises  the  laws  of  the  composition 
and  chemical  behavior  of  compounds;  physical  chemistry 
treats  of  the  physical  properties  of  compounds,  of  homo- 
geneous mixtures,  and  of  the  physical  phenomena  (thermal, 
electrical,  etc.)  accompanying  the  transformations  of  sub- 
stances in  general.  Applied  chemistry  comprises  all  the 
facts  and  methods  of  chemistry  that  find  practical  employ- 
ment. The  most  important  subdivisions  of  this  branch  are : 
(1)  Biological  chemistry,  including  the  facts  connected 
with  physiological  and  pathological  phenomena  in  animals 
and  plants;  (2)  Agricultural  chemistry,  which  deals  with 
the  problems  of  rural  economy;  and  (3)  Industrial,  Tech- 


CHEMISTRY  AND  ITS  DEVELOPMENT      197 

nological,  or  Practical  chemistry,  which  deals  with  the  uses 
of  chemistry  in  the  arts  and  manufactures. 

THE  METHODS  OF  CHEMICAL  PHILOSOPHY.  Like  any 
other  science,  chemistry  may  use  two  different  ways  of  dis- 
covering and  demonstrating  its  general  principles.  On 
the  one  hand— and  this  is  the  surest  way— a  principle  may 
be  induced  from  a  large  number  of  experimental  observa- 
tions; it  is  then  nothing  but  a  general  statement  of  a 
general  fact  and  is  termed  an  empirical  law.  Thus  the  prin- 
ciple of  the  conservation  of  matter  is  an  empirical  law. 
Perhaps  this  law  may  suggest  itself  a  priori;  but  as  a  law 
of  science  it  has  been  induced  from  facts  established  by 
the  balance.  On  the  other  hand,  there  are  problems  which 
cannot  be  attacked  by  experiment.  Thus  the  problem  of 
the  ultimate  structure  of  matter  lies  far  beyond  our  power 
of  direct  observation;  yet  it  is  intimately  connected  with 
the  correlation  of  substances,  and  therefore  chemistry  is 
compelled  to  consider  it  for  purely  practical  reasons.  In 
cases  of  this  nature,  chemistry,  like  any  other  science,  and 
like  speculative  philosophy,  makes  some  plausible  assump- 
tion, termed  an  hypothesis.  Like  speculative  philosophy, 
it  developes  the  hypothesis,  conbines  it,  if  necessary,  with 
other  assumptions,  and  thus  builds  up  a  theory.  But  at 
this  point,  where  speculative  research  reaches  its  ne  plus 
ultra,  the  work  of  the  scientist  really  begins.  The  general 
principles  forming  part  of  the  theory  are  busily  applied  to 
phenomena  capable  of  direct  observation,  and  then,  if 
their  correctness  is  indicated  by  actual  experiment,  they 
become  theoretical  laws.  A  scientific  theory  has  for  its 
object,  first  to  correlate  seemingly  different  facts,  and, 
secondly,  to  throw  light  on  the  road  of  investigation  and 
lead  to  the  establishment  of  new  facts.  Thus,  the  atomic 
theory  has  correlated  the  various  substances  with  regard 
to  their  composition  and  constitution,  and  it  has  revealed 
the  existence  of  innumerable  compounds  many  of  which 
have  since  been  actually  prepared— an  achievement  not 
unlike  the  discovery  of  Neptune  by  theoretical  astronomy. 


198  MODERN  SCIENCE  READER 

ALCHEMY1 

Alchemy  is  to  modern  chemistry  what  astrology  is  to 
astronomy,  or  legend  to  history.  In  the  eye  of  the  astrol- 
oger, a  knowledge  of  the  stars  was  valuable  as  a  means  of 
foretelling,  or  even  of  influencing,  future  events.  In  like 
manner,  the  genuine  alchemist  toiled  with  his  crucibles 
and  alembics,  calcining,  subliming,  distilling,  with  two 
grand  objects,  as  illusory  as  those  of  the  astrologer— to  dis- 
cover, namely,  (1)  the  secret  of  transmuting  the  baser 
metals  into  gold  and  silver,  and  (2)  the  means  of  indefi- 
nitely prolonging  human  life. 

Tradition  points  to  Egypt  as  the  birthplace  of  the  science, 
and  the  most  probable  etymology  of  the  name  is,  as  was 
pointed  out  above,  that  it  is  connected  with  the  most 
ancient  and  native  name  of  Egypt,  Chcmi  (the  scripture 
Cham  or  Ham).  The  Greeks  and  Romans  under  the 
empire  would  seem  to  have  become  acquainted  with  it  from 
the  Egyptians;  there  is  no  reason  to  believe  that  either 
people  had  in  early  times  either  the  name  or  the  thing. 
Chemia  occurs  in  the  lexicon  of  Suidas,  written  about  the 
eleventh  century,  and  is  explained  by  him  to  be  "the  con- 
version of  silver  and  gold."  It  is  to  the  Arabs,  from  whom 
Europe  got  the  name  and  the  art,  that  the  term  owes  the 
prefixed  article  al  (the)  ;  as  if  chemia  had  been  a  generic 
term  embracing  all  chemical  operations,  such  as  the  decoct- 
ing and  compounding  of  ordinary  drugs,  and  the  chemia 
(al-chemy)  the  term  to  denote  the  grand  operation  of 
transmuting  metals— the  chemistry  of  chemistries.  The 
Roman  Emperor  Caligula  is  said  to  have  instituted  exper- 
iments for  the  producing  of  gold  out  of  orpiment  (sulphide 
of  arsenic)  ;  and  in  the  time  of  Diocletian,  the  passion  for 
this  pursuit,  conjoined  with  magical  arts,  had  become  so 
prevalent  in  the  empire  that  that  emperor  is  said  to  have 
ordered  all  Egyptian  works  treating  of  the  chemistry  of 

1From    The   New   International   Encyclopaedia,  vol.    i,    page   289. 
Copyright  1902,  1904,  1905,  190G,  1907,  1909  by  Dodd,  Mead  &  Co. 


CHEMISTRY  AND  ITS  DEVELOPMENT      199 

gold  and  silver  to  be  burned.  For  at  that  time  multitudes 
of  books  on  this  art  were  appearing,  written  by  Alexandrine 
monks  and  by  hermits,  but  bearing  famous  names  of 
antiquity,  such  as  Democritus,  Pythagoras  and  Hermes. 

At  a  later  period  the  Arabs  took  up  the  art,  and  it  is 
to  them  that  European  alchemy  is  directly  traceable.  The 
school  of  polypharmacy,  as  it  has  been  called,  flourished  in 
Arabia  during  the  caliphate  of  Abbassides.  The  earliest 
work  of  this  school  now  known  is  the  Summa  Perfedionis, 
or  "Summit  of  Perfection",  composed  by  Geber  about  the 
eighth  century;  it  is  consequently  the  oldest  book  on 
chemistry  proper  in  the  world.  It  contains  so  much  of 
what  sounds  like  jargon  to  modern  ears,  that  Dr.  Johnson 
ascribes  the  origin  of  the  word  "gibberish"  to  the  name  of 
the  compiler.  Yet,  when  viewed  in  its  true  light,  it  is  a 
wonderful  performance.  It  is  a  kind  of  text-book,  or  col- 
lection of  all  that  was  then  known  and  believed.  It  ap- 
pears that  these  Arabian  polypharmacists  had  long  been 
engaged  in  firing  and  boiling,  dissolving  and  precipitating, 
subliming  and  coagulating  chemical  substances.  They 
worked  with  gold  and  mercury,  arsenic  and  sulphur,  salts 
and  acids,  and  had,  in  short,  become  familiar  with  a  large 
range  of  what  are  now  called  chemicals.  Geber  taught 
that  there  are  three  elemental  chemicals— mercury,  sul- 
phur and  arsenic.  These  substances,  especially  the  first 
two,  seem  to  have  fascinated  the  thoughts  of  the  alchemists 
by  their  potent  and  penetrating  qualities.  They  saw  mer- 
cury dissolve  gold,  the  most  incorruptible  of  matters,  as 
water  dissolves  sugar;  and  a  stick  of  sulphur  presented  to 
hot  iron  penetrates  it  like  a  spirit,  and  makes  it  run  down 
in  a  shower  of  solid  drops,  a  new  and  remarkable  substance 
possessed  of  properties  belonging  to  neither  iron  nor  to 
sulphur.  The  Arabians  held  that  the  metals  are  com- 
pound bodies,  made  up  of  mercury  and  sulphur  in  differ- 
ent proportions.  With  these  very  excusable  errors  in 
theory,  they  were  genuine  practical  chemists.  They  toiled 
away  at  the  art  of  making  "many  medicines"  (poly- 


200  MODERN  SCIENCE  READER 

pharmacy)  out  of  various  mixtures  of  such  chemicals  as 
they  knew.  They  had  their  pestles  and  mortars,  their  cru- 
cibles and  furnaces,  their  alembics  and  aludels,  their  ves- 
sels for  infusion,  for  decoction,  for  cohobation,  sublimation, 
fixation,  lixiviation,  filtration,  coagulation,  etc.  Their 
scientific  creed  was  transmutation,  and  their  methods  ¥were 
mostly  blind  gropings;  and  yet  in  this  way  they  found  out 
many  a  new  substance  and  invented  many  a  useful  process. 
From  the  Arabs  alchemy  found  its  way  through  Spain 
into  Europe,  and  speedily  became  entangled  with  the 
fantastic  subtleties  of  the  scholastic  philosophy.  In  the 
middle  ages  it  was  chiefly  the  monks  that  occupied  them- 
selves with  alchemy.  Pope  John  XXII  took  great  delight 
in  it,  though  it  was  after  forbidden  by  his  successor.  The 
earliest  authentic  works  on  European  alchemy  now  extant 
are  those  of  Roger  Bacon  (died  about  1294)  and  Albertus 
Magnus.  Bacon  appears  rather  the  earlier  of  the  two  as 
a  writer,  and  is  really  the  greatest  man  in  all  the  school. 
He  was  acquainted  with  gunpowder.  Although  he  con- 
demned magic,  necromancy,  charms  and  all  such  things,  he 
believed  in  the  convertibility  of  the  inferior  metals  into 
gold,  but  did  not  profess  to  have  ever  effected  the  conver- 
sion. He  had  more  faith  in  the  elixir  of  life  than  in  gold 
making.  He  followed  Geber  in  regarding  potable  gold— 
that  is  gold  dissolved  in  aqua  regia—as  the  elixir  of  life. 
Urging  it  on  the  attention  of  Pope  Nicholas  IV  he  informed 
his  Holiness  of  an  old  man  who  had  found  some  yellow 
liquor  (the  solution  of  gold  is  yellow)  in  a  golden  vial  when 
plowing  one  day  in  Sicily.  Supposing  it  to  be  dew  he 
drank  it ;  he  was  thereupon  transformed  into  a  hale,  robust 
and  highly  accomplished  youth.  Bacon  no  doubt  took 
many  a  dose  of  this  golden  water  himself.  Albertus 
Magnus  had  a  great  mastery  of  the  practical  chemistry  of 
his  times.  He  was  acquainted  with  alum,  caustic  alkali, 
and  the  purification  of  the  noble  metals  by  lead.  In  addi- 
tion to  the  sulphur-and-mercury  theory  of  metals,  drawn 
from  Geber,  he  regarded  the  element  water  as  still  nearer 


CHEMISTRY  AND  ITS  DEVELOPMENT      201 

the  soul  of  nature  than  either  of  these  bodies.  He  appears, 
indeed,  to  have  thought  it  the  primary  matter,  or  the 
radical  source  of  all  things— an  opinion  held  by  Thales, 
the  father  of  Greek  speculation.  Thomas  Aquinas  also 
wrote  on  alchemy,  and  was  the  first  to  employ  the  word 
amalgam.  Ramond  Lulty  is  another  great  name  in  the 
annals  of  alchemy.  His  writings  are  much  more  disfigured 
by  unintelligible  jargon  than  those  of  Bacon  and  Albertus 
Magnus.  He  was  the  first  to  introduce  the  use  of  chemical 
symbols,  his  system  consisting  of  a  scheme  of  arbitrary 
hieroglyphics.  He  made  much  of  the  spirit  of  wine  (the 
art  of  distilling  spirits  would  seem  then  to  have  been 
recent),  imposing  on  it  the  name  of  aqua  vitae  ardens.  In 
his  enthusiasm  he  pronounced  it  the  very  elixir  of  life. 

But  more  famous  than  all  was  Paracelsus  (1493-1541, 
A.D.),  in  whom  alchemy  proper  may  be  said  to  have  cul- 
minated. He  held  that  the  elements  of  compound  bodies 
were  salt,  sulphur  and  mercury— representing  respectively 
earth,  air  and  water;  fire  being  already  regarded  as  an 
imponderable— but  these  substances  were  in  his  system 
purely  representative.  All  kinds  of  matter  were  reducible 
under  one  or  the  other  of  these  typical  forms ;  every  thing 
was  either  a  salt,  a  sulphur,  or  a  mercury,  or,  like  the 
metals,  it  was  a  "mixt"  or  compound.  There  was  one  ele- 
ment, however,  common  to  the  four ;  a  fifth  essence  or 
"quintessence"  of  creation;  an  unknown  and  only  true 
element,  of  which  the  four  generic  principles  were  nothing 
but  derivative  forms  or  embodiments.  In  other  words, 
Paracelsus  inculcated  the  dogma  that  there  is  only  one 
real  elementary  matter — nobody  knows  what.  This  one 
prime  element  of  things  he  appears  to  have  believed  to  be 
the  one  universal  solvent  of  which  the  alchemists  were  in 
quest,  and  to  express  which  he  introduced  the  term 
alcakest—%  word  of  unknown  etymology  but  supposed  by 
some  to  be  composed  of  two  German  words  all'  Geist,  "all 
spirit/'  He  seems  to  have  had  the  notion  that  if  this  fifth 
essence  or  quintessence  could  be  got  at,  it  would  prove  to 


202  MODERN  SCIENCE  READER 

be  at  once  the  philosopher's  stone,  the  universal  medicine, 
and  the  irresistible  solvent. 

After  Paracelsus,  the  alchemists  of  Europe  became  di- 
vided into  two  classes.  The  one  class  was  composed  of 
men  of  diligence  and  sense,  who  devoted  themselves  to  the 
discovery  of  new  compounds  and  reactions— practical 
workers  and  observers  of  facts,  and  the  legitimate  ances- 
tors of  the  chemists  of  the  era  of  Lavoisier.  The  other 
class  took  up  the  visionary  and  fantastical  side  of  the 
older  alchemy,  and  carried  it  to  a  degree  of  extravagance 
previously  unknown.  Instead  of  useful  work,  they  com- 
piled mystical  trash  into  books,  and  fathered  them  on 
Hermes,  Aristotle,  Albertus  Magnus,  Paracelsus  and  other 
really  great  men.  Their  language  is  a  farrago  of  mystical 
metaphors,  full  of  "red  bridegrooms"  and  "lily  brides", 
"green  dragons",  "ruby  lions",  "royal  baths",  "waters 
of  life",  etc.  The  seven  metals  correspond  to  the  seven 
planets,  the  seven  cosmical  angels,  and  the  seven  openings 
of  the  head— the  eyes,  the  ears,  the  nostrils  and  the  mouth. 
Silver  was  Diana,  gold  was  Apollo,  iron  was  Mars,  tin  was 
Jupiter,  lead  was  Saturn,  etc.  They  talk  forever  of  the 
power  of  attraction,  which  drew  all  men  and  women  after 
the  possessor;  of  the  alcahest,  and  the  grand  elixir  which 
was  to  confer  immortal  youth  upon  the  student  who  should 
prove  himself  pure  and  brave  enough  to  kiss  and  quaff  the 
golden  draught.  There  was  the  great  mystery,  the  mother 
of  the  elements,  the  grandmother  of  the  stars.  There  was 
the  philosopher's  stone  and  there  was  the  philosophical 
stone.  The  philosophical  stone  was  younger  than  the  ele- 
ments, yet  at  her  virgin  touch  the  grossest  calx  (ore) 
among  them  all  would  blush  before  her  into  perfect  gold. 
The  philosopher's  stone,  on  the  other  hand,  was  the  first- 
born of  nature,  and  older  than  the  king  of  metals.  Those 
who  had  attained  full  insight  into  the  arcana  of  the 
science  were  styled  "wise";  those  who  were  only  striving 
after  the  light  were  termed  philosophers;  while  the  ordi- 
nary votaries  of  the  art  were  called  adepts.  It  was  these 


CHEMISTRY  AND  ITS  DEVELOPMENT      203 

visionaries  that  formed  themselves  into  Rosier ucian  societies 
and  other  secret  associations.  It  was  also  in  connection 
with  this  mock  alchemy,  mixed  up  astrology  and  magic, 
that  quackery  and  imposture  so  abounded,  as  is  depicted 
by  Scott  in  the  character  of  Dousterswivel  in  the  Anti- 
quart/.  Designing  knaves  would,  for  instance,  make  up 
large  nails,  some  of  iron  and  some  of  gold,  and  lacquer 
them  so  that  they  appeared  to  be  common  nails,  and  when 
their  credulous  and  avaricious  dupes  saw  them  extract  from 
what  seemed  to  be  plain  iron  an  ingot  of  gold,  they  were 
ready  to  advance  any  sum  that  the  knaves  pretended  to  be 
necessary  for  applying  the  process  on  a  large  scale.  It  is 
from  this  degenerate  and  effete  school  that  the  prevailing 
notion  of  alchemy  is  derived— a  notion  that  is  unjust  to 
the  really  meritorious  alchemists  who  paved  the  way  for 
the  modern  science  of  chemistry. 

Priestley,  Lavoisier  and  Scheele  by  the  use  of  the  balance 
tested  the  results  of  alchemy,  and  hence  the  fundamental 
ideas  of  modern  chemistry  were  born;  but  the  work  had 
already  been  begun  by  men  of  genius,  such  as  Robert 
Boyle,  Bergmann  and  others.  It  is  interesting  to  observe 
that  the  doctrine  of  the  transmut ability  of  metals— a  doc- 
trine which  it  was  at  one  time  thought  that  modern  chem- 
istry had  utterly  exploded— receives  not  a  little  counte- 
nance from  a  variety  of  facts  every  day  coming  to  light ;  not 
to  speak  of  the  periodic  law  of  the  elements,  which,  while 
separating  the  elements  as  a  class  from  all  other  chemical 
substances,  seems  to  indicate  the  existence  of  unknown 
relations  between  the  elements  themselves.1 

irTlie  literature  of  alchemy  is  enormous.  Those  who  desire  to  read 
more  about  it  may  consult  the  following  works:  H.  Kopp,  Die 
Alchemie  in  dlterer  und  neurer  Zeit  (1886),  see  a  review  of  it  in  this 
volume;  J.  von  Liebig,  Familiar  Letters  on  Chemistry  (London, 
1851)  ;  F.  Hofer,  Histoire  de  la  CMmie  (Paris,  1869) ;  M.  Berthelot, 
Les  Origines  de  I'Alchimie  (Paris,  1885);  etc. 


204  MODERN  SCIENCE  READER 

HISTORY  OP  CHEMISTRY1 

The  history  of  ancient  philosophy  records  certain  theories 
of  matter  which  have  had  a  directing  influence  on  chemical 
thought  during  later  centuries.  The  most  important  ideas 
date  from  the  fifth  century,  B.C.  Empedocles  (c.  490-30 
B.C.),  who  may  have  derived  his  views  from  the  ancient 
philosophers  of  the  East,  held  that  air,  water,  earth  and 
fire  are  the  four  elements  unrelated  to  one  another  and 
forming  the  basis  of  the  universe.  Aristotle  (384-322  B.C.) 
added  a  fifth  element,  ousia,  a  purely  spiritual  substance 
pervading  the  infinity  of  space.  During  the  Middle  Ages 
not  a  little  energy  was  lost  in  researches  after  this  "fifth 
essence"  which,  by  confusion  of  ideas,  came  to  be  regarded 
as  a  fifth  elementary  form  of  matter.  To  Aristotle  the 
material  elements  were  not  altogether  different  from  one 
another,  but  were  forms  of  a  primary  substance  differen- 
tiated by  properties—  as  dry,  moist,  hot,  cold—  that  were 
not  essential  to  its  nature.  Hence,  later,  the  alchemist  's 
attempt  to  turn  metals  into  one  another,  crowned  by  the 
belief  that  such  transmutations  cannot  be  effected  by  any 
known  means.  The  conception  of  the  atom  dates  from 
Democritus  (c.  460-370  B.C.),  who  held  that  all  bodies  are 
made  up  of  the  atoms  of  one  and  the  same  substance,  and 
that  the  difference  exhibited  by  the  various  forms  of 
matter  are  due  entirely  to  the  differences  in  the  size  and 
shape  of  the  atoms.  It  is  hardly  necessary  to  state  that  if 
this  undeveloped  idea  of  Democritus  had  not  furnished  a 
suggestion  that  led  to  the  building  up  of  a  useful  chemical 
doctrine,  it  would  deserve  no  mention  in  the  history  of 
science.  It  is  thus  clear  that  the  ancients  did  nothing 
directly  to  the  building  up  of  a  science  of  chemistry. 
Indeed,  how  much  chemical  ,  knowledge  can  we  expect  to 
find  in  an  age  when  a  man  like  Aristotle  did  not  hesitate 


The  New  International  Encyclopaedia,  vol.   iv,  page  566. 
Copyright  1903,  1904,  1905,  1906,  1909  by  Dodd,  Mead  &  Co. 


CHEMISTRY  AND  ITS  DEVELOPMENT      205 

to  assert  that  "a  vessel  will  hold  as  much  water  when 
filled  with  ashes  as  when  empty"? 

However,  the  ancients  knew  some  facts  which  lie  within 
the  scope  of  modern  chemistry.  Most  of  that  knowledge 
was  gained  empirically  by  the  Egyptians,  and  was  by  them 
communicated  to  the  Jews  and  Phoenicians,  and  later  to 
the  Greeks  and  Romans.  The  metallurgy  of  gold,  silver, 
copper,  iron,  lead,  tin,  mercury,  and  perhaps  zinc,  and  the 
preparation  of  certain  alloys,  were  known  at  quite  an  early 
date.  The  Egyptians  had  highly  developed  the  art  of 
making  glass  and  of  coloring  it  by  means  of  certain 
metallic  oxides,  and  many  extant  -  specimens  of  Egyptian 
pottery  are  beautifully  enameled  in  various  colors.  The 
art  of  dyeing  fabrics  by  the  aid  of  mordants  had  likewise 
been  developed  at  an  early  date,  and  many  mineral  and 
organic  coloring  matters  were  known  to  the  Egyptians, 
Phoenicians  and  Jews.  The  Egyptians  were  also  probably 
the  first  to  compound  substances  for  medicinal  purposes. 

The  arts  of  metallurgy  and  of  dyeing  remained  through 
the  Middle  Ages  practically  what  they  had  been  in  Egypt 
long  before  the  beginning  of  our  era.  Nevertheless,  the 
alchemists,  in  their  search  after  the  philosopher's  stone, 
discovered  methods  of  preparing  many  new  substances, 
perfected  many  processes  of  manipulation,  and  thus  slowly 
paved  the  way  for  future  investigators.  Bismuth  and 
antimony,  sulphuric,  hydrochloric  and  nitric  acids,  the 
chloride  and  carbonate  of  ammonium,  the  nitrates  of 
potassium  and  silver,  compounds  of  mercury,  antimony 
and  arsenic— these  and  many  other  important  substances 
were  first  prepared  and  their  properties  were  first  studied 
by  the  alchemists.  Of  course  the  interpretation  of  the 
known  facts  was  absurd,  based  as  it  often  was  upon  the 
most  groundless  assumptions— for  instance,  the  assumption 
that  most  substances,  and  all  metals  contained  sulphur.  As 
to  the  compounds  of  carbon,  the  alchemists  did  hardly  any- 
thing toward  laying  a  foundation  for  future  organic 
chemistry,  although  they  learned  to  concentrate  aqueous 


206  MODERN  SCIENCE  READER 

acetic  acid  by  distillation  and  to  prepare  a  few  metallic 
acetates,  and  were  familiar  with  certain  reactions,  such  as 
the  transformation  of  ordinary  alcohol  under  the  influence 
of  sulphuric  acid,  the  formation  of  certain  esters,  etc.  A 
number  of  substances  derived  from  the  organic  world  were 
also  used  for  medical  purposes ;  but  it  was  not  until  the 
beginning  of  the  ' ' iatrochemical' '  period  (iatros,  physi- 
cian) that  the  art  of  preparing  substances  began  to  be  looked 
upon  as  the  handmaiden  of  medicine.  Alchemy  proper 
had  only  two  great  objects  in  view— to  ennoble  the  base 
metals  and  to  prolong  life  indefinitely— and  these  remained 
the  aim  of  some  of  the  best  men  even  to  the  close  of  the 
era  of  iatrochemistry,  and  even  the  scientific  achievements 
of  more  recent  times  have  not  sufficed  to  banish  the  fancy 
completely. 

The  first  great  iatrochemist  was  Paracelsus  (1493-1541), 
who  taught  that  the  aim  of  chemistry  was  the  preparation, 
not  of  gold,  but  of  therapeutic  agents.  Adopting  a  view 
current  among  alchemists  prior  to  his  time,  he  held  that, 
every  thing  being  composed  of  sulphur,  mercury  and  salt, 
if  the  amounts  of  these  happen  to  rise  above  or  fall  below 
the  normal  quantities  that  are  in  the  animal  body,  the 
result  is  a  condition  of  disease.  Hence,  disease  must  be 
combated  by  chemical  means.  Paracelsus  therefore  devoted 
himself  to  pharmacy  and  medical  chemistry,  and  soon  be- 
came famous  through  the  many  happy  cures  that  he 
actually  succeeded  in  effecting.  Unfortunately  the  adven- 
turous life  he  led,  and  his  gross  lack  of  modesty,  aroused 
suspicion  in  many,  and  the  bitterest  opposition  among  the 
more  conservative  members  of  the  medical  profession,  and 
obscured  his  fame  and  greatly  diminished  the  sphere  of 
his  influence.  Nevertheless,  his  great  work  was  accom- 
plished; pure  alchemy  had  received  at  his  hands  the  first 
powerful  blow,  pharmacy  had  been  firmly  linked  to  chem- 
ical science,  and  medicine  had  been  aroused  from  the  torpor 
of  many  centuries. 

Following  in  the  steps  of  Paracelsus  came  Turquet  de 


CHEMISTRY  AND  ITS  DEVELOPMENT      207 

May  erne  (1573-1655),  Andreas  Libavius  (M616),  Oswald 
Croll,  Adrian  van  Mynsicht,  and  the  great  Van  Helmont 
(1577-1644).  Van  Helmont  not  only  realized  that  the 
processes  of  life,  in  health  and  disease,  are  largely  depend- 
ent upon  chemical  changes,  but  he  abandoned  the  abitrary 
assumptions  of  Paracelsus  concerning  the  chemical  basis 
of  the  animal  body,  and  his  keen  experimental  researches 
imparted  a  powerful  impulse  to  the  development  of  scien- 
tific medicine.  Equally  if  not  more  important  was  his  recog- 
nition of  the  fact  that  there  may  be  other  gases  than  air, 
and  that  atmospheric  air, ' '  carbonic  acid, ' '  hydrogen,  marsh 
gas  and  ''sulphurous  acid"  may  be  quite  different  from 
one  another.  In  certain  special  cases  Van  Helmont  suc- 
ceeded in  showing  that  substances  are  not  lost,  either  qual- 
itatively or  quantitatively,  when  they  enter  into  chemical 
combination,  and  that  they  may  be  re-obtained  from  the 
resulting  compounds.  Yet  he  believed  in  the  possibility  of 
making  gold,  and,  strange  to  relate,  among  the  absurdities 
found  in  his  writings  is  the  assertion  that  mice  may  be 
spontaneously  produced  in  buckets  filled  with  soiled  linen 
and  wheat  flour !  But  if  the  spirit  of  the  time  permitted 
such  beliefs,  so  much  more  deserved  is  his  place  among  the 
best  names  of  both  chemistry  and  medicine.  Other  im- 
portant names  connected  with  iatrochemistry  are  those  of 
Silvius  (1614-1672)  and  Tachenius.  Silvius  was  the  first 
to  grasp  the  similarity  between  the  processes  of  respiration 
and  combustion,  and,  recognizing  the  distinction  between 
arterial  and  venous  blood,  he  understood  that  the  bright 
color  of  the  former  was  due  to  the  action  of  the  air.  Di- 
gestion, too,  he  considered  as  a  purely  chemical  process. 
His  pupil,  Tachenius,  was  the  first  to  clearly  recognize  that 
salts  are  substances  formed  by  the  union  of  acids  and 
bases;  he  studied  the  composition  and  properties  of  many 
substances,  invented  a  number  of  interesting  qualitative 
tests,  and  even  subjected  a  few  reactions  to  quantitative 
investigation ;  determining,  for  instance,  the  gain  in  weight 
involved  in  the  oxidation  of  lead. 


208  MODERN  SCIENCE  READER 

The  age  of  iatrochemistry  marks  a  great  period  4n 
chemical  history.  During  this  period,  for  the  first  time 
we  find  many  thoughtful  men  making  an  endeavor  to  free 
themselves  from  the  preconceived  ideas  of  the  past,  and  to 
approach  nature  in  a  critical  spirit  and  with  a  curiosity 
purely  scientific.  With  iatrochemistry  was  thus  born  the 
possibility  of  chemical  progress.  But  this  is  not  the  only 
thing  for  which  mankind  is  indebted  to  that  period.  For, 
while  the  iatrochemists  were  preparing  the  first  material 
for  the  very  foundation  of  future  chemistry,  others  were 
busy  developing  industries  which  have  since  become 
affiliated  with  our  science.  Foremost  among  these  men 
were  Agricola,  Palissy  and  Glauber.  Georg  Agricola  (1490- 
1555)  rendered  great  service  to  mining  and  metallurgy, 
introducing  rational  methods  into  the  former  and  perfect- 
ing many  of  the  processes  of  the  latter.  His  splendid 
treatise  on  metallurgy,  in  which  these  processes  were 
described  for  the  first  time,  long  remained  the  standard 
work  on  its  subject.  Besides,  he  introduced  a  practical 
system  for  the  classification  of  minerals,  based  on  their 
physical  properties,  such  as  color,  hardness,  etc.  Bernhard 
Palissy  (c.  1510-89),  considering  worthless  and  ridiculous 
the  efforts  of  alchemy,  devoted  himself  to  experimental 
research  in  ceramic  art,  and  invented  a  number  of  valu- 
able methods  of  coloring  and  enameling  articles  of  pottery. 
Johann  Rudolf  Glauber  (1604-1668)  improved  many 
processes  of  dyeing  and  prepared  a  number  of  useful  salts, 
including  sodium  sulphate  ("Glauber's  salt"),  the  chlo- 
rides of  zinc,  tin,  arsenic,  copper,  lead  and  iron,  the  nitrate 
of  ammonium,  tartar  emetic,  etc.  He  even  succeeded  in 
gaining  an  insight  in  the  rationale  of  certain  processes ;  but 
this  did  not  prevent  him  from  adhering  to  the  most  fan- 
tastic of  the  absurdities  of  alchemy  to  the  very  end  of  his 
life.  In  connection  with  the  iatrochemical  period,  refer- 
ence must  be  made  to  the  wonderful  development  of  the 
art  of  making  articles  of  glass,  and  to  the  rapid  progress 
of  the  liquor  industry,  which  had  only  been  founded 


CHEMISTRY  AND  ITS  DEVELOPMENT      209 

towards  the  end  of  the  fifteenth  century— i.e.,  a  short  time 
before  the  commencement  of  the  period.  As  to  scientific 
pharmacy,  we  have  already  stated  that  its  beginning  coin- 
cides with  that  of  iatrochemistry,  and  it  is  hardly  necessary 
to  add  that  the  latter  enriched  it  with  many  new  prepara- 
tions, and  with  a  knowledge  of  the  medicinal  properties  of 
substances  already  known. 

About  the  middle  of  the  seventeenth  century  iatro- 
chemistry came  to  a  sudden  decline.  That  this  had  to 
happen  sooner  or  later  is  clear,  if  we  consider  that  a  true 
medical  chemistry  could  not  possibly  flourish  until  chem- 
istry itself  was  placed  on  a  sound  basis,  and  before  anatomy 
and  physiology  had  attained  a  stage  of  serious  development. 
The  iatrochemists  had  evidently  misdirected  their  efforts, 
and  if  we  should  in  our  present  structure  of  chemistry 
mark  the  parts  established  by  them,  we  would  find  that 
their  lasting  contributions  were  very  few.  The  historical 
importance  of  the  period  lies  chiefly  in  the  fact  that  with 
it  came  a  revolution  against  traditional  errors  and  a 
change  in  the  direction  of  research. 

In  the  seventeenth  century  we  find  the  Englishman, 
Eobert  Boyle  (1627-91),  grasping  truth  with  an  insight 
unprecedented,  and  in  many  respects  as  yet  unsurpassed. 
Boyle  understood  that  chemistry  must  be  treated  as  an 
independent  science— i.e.,  primarily  without  reference  to 
applications  of  any  sort,  and  that  only  in  this  manner 
could  the  relationships  between  chemical  phenomena  proper 
be  discovered.  He  maintained  that  chemists  should  con- 
sider as  an  element  only  a  substance  which,  in  spite  of 
exhaustive  actual  efforts,  they  have  not  succeeded  in  decom- 
posing. And  even  this  method,  though  necessary  and 
sufficient  for  the  purposes  of  science,  he  did  not  regard  as 
proving  the  elementary  nature  of  substances  beyond  doubt. 
Still,  he  was  inclined  to  consider  the  metals  as  elements, 
and,  proving  experimentally  that  the  products  of  the  dis- 
tructive  distillation  of  wood  are  compounds,  he  refuted 
the  opinion— then  generally  prevalent— that  dry  distilla- 
14 


210  MODERN  SCIENCE  READER 

tion  breaks  up  substances  into  their  elements.  He  further 
defined  the  distinction  between  a  chemical  compound  and 
a  mixture ;  he  maintained  that  the  properties  of  a  chemical 
compound  are  quite  different  from  those  of  its  components, 
and  that  in  a  mixture  each  retained  its  characteristic  prop- 
erties practically  unaffected.  Above  all,  he  earnestly 
warned  chemists  against  adopting  hypotheses  and  general 
theories  a  priori.  Theories  are  necessary;  but  unless  they 
are  generalizations  cautiously  made  from  observed  facts, 
they  may  be  dangerously  misleading. 

Boyle's  views  are  now  accepted  universally.  Had  he 
grasped  and  succeeded  in  spreading  abroad  one  more  idea 
—viz.,  the  absolute  necessity  of  quantitative  investigation- 
he  would  doubtless  have  become  the  founder  of  the  science 
of  chemistry— that  is  to  say,  with  him  would  have  com- 
menced the  epoch  enlightened  by  truth  and  free  from 
fundamental  errors.  This  he  did  not  accomplish;  nor  was 
it  possible  to  accomplish  it  before  the  characteristics  of 
gaseous  matter  came  to  be  known  better  than  they  were  in 
his  day.  And  so  it  came  about  that  chemists  failed  to 
appreciate  his  great  warning  against  hypotheses  that  are 
not  rigidly  correlated  with  facts,  and  adopted  a  belief  in 
a  fiery  "phlogiston";  thus  creating  a  period  of  darkness 
that  lasted  a  century.  It  must  be  remembered  that  the 
important  phenomena  of  what  we  now  call  oxidation  en- 
gaged the  attention  of  chemists  toward  the  end  of  the 
seventeenth  century  and  through  the  entire  eighteenth 
century.  These  phenomena  were  explained  by  the  sup- 
posed existence  of  ' '  phlogiston, ' '  a  substance  that  may  have 
been  first  produced  in  the  mind  of  some  alchemist,  but  the 
first  clear  reference  to  which,  under  the  name  of  terra 
pinquis,  we  find  in  the  works  of  Becher  (1635-82).  Stahl 
(1660-1734)  named  it  phlogiston,  endowed  it  with  certain 
imaginary  properties,  and  used  it  as  the  basis  of  a  doctrine 
that  was  soon  accepted  throughout  the  civilized  world. 

To  give  a  clear  and  precise  account  of  this,  as  of  any 
other  erroneous  doctrine,  is  a  matter  of  considerable  dif- 


CHEMISTRY  AND  ITS  DEVELOPMENT      211 

ficulty.  For  when  ingenious  men  are  dominated  by  error, 
they  usually  mold  it  in  a  variety  of  forms  to  give  it  the 
appearance  of  truth  and  render  it  consistent  with  itself. 
The  phlogistonians  handled  their  hypothesis  with  much 
dexterity.  Yet  their  thought,  lacking  the  character  of  quan- 
titative precision,  was  weak;  for  quantitative  conceptions, 
while  already  mastered  by  the  physicists,  were  still  in  a 
state  of  confusion  in  the  minds  of  the  chemists.  Distin- 
guishing clearly  between  the  weight  of  bodies  and  their 
specific  gravity,  we  have  no  difficulty  in  understanding 
that  although  water  vapor  is  lighter  than  air,  its  addition 
to  a  given  body  must  increase  the  weight  of  the  latter, 
because  water,  whether  liquid  or  vaporized,  has  weight. 
Stahl  believed  that  the  conversion  of  a  "calx"  (i.e.  a  metal- 
lic oxide)  into  a  metal  was  caused  by  the  addition  of 
phlogiston.  He  knew  that  the  conversion  was  accompanied 
by  the  diminution  of  weight;  but  from  this  fact  he  only 
deduced  that  phlogiston  must  be  '  *  lighter  than  air, ' '  failing 
to  grasp  that  such  an  addition  may  make  a  bod}'  lighter^ 
in  the  sense  of  producing  one  of  lower  specific  gravity, 
but  necessarily  make  it  heavier  in  the  sense  of  increasing 
its  absolute  weight.  It  is  more  probable,  however,  that 
Stahl  understood  this  in  a  general  way,  but  thought  that 
the  metals  had  a  lower  specific  gravity  than  their  calces. 
At  least,  Juncker,  a  pupil  of  Stahl's,  asserts  this  about 
metals  and  calces  as  a  matter  of  fact,  although  Boyle  had 
long  since  shown  experimentally  that  the  specific  gravity 
of  metals  is  really  higher  than  that  of  their  calces.  Much 
more  extraordinary  is  the  conception  that  we  find  in  the 
writings  of  Guyton  de  Morveau,  Macquer  and  others,  who 
taught  that  phlogiston  had  less  than  no  weight!  Stahl  con- 
ceived of  phlogiston  as  a  fiery  principle,  "materia  aut  prin- 
cipium  ignis,  -non  ipsi  ignis.'9  Seeing  that  charcoal  burns 
up  completely,  and  is  capable  of  producing  metals  by 
adding  itself,  as  he  thought,  to  their  calces,  he  considered 
charcoal  as  made  up  almost  entirely  of  phlogiston.  Caven- 
dish knowing  that  "inflammable  air"  is  given  off  when 


212  MODERN  SCIENCE  READER 

metals  are  dissolved  in  acids,  adopted  the  view  that  inflam- 
mable air  (hydrogen)  was  phlogiston,  with  which  metals 
part  on  coming  in  contact  with  acids.  An  inconvenient  fact 
in  connection  with  the  phlogistic  theory  was  that  combus- 
tion, including  the  transformation  of  metals  into  calces, 
could  only  take  place  in  the  air.  Stahl  and  his  followers 
referred  to  this  fact  as  if  it  were  quite  natural  that  if  phlo- 
giston was  to  be  absorbed  from  metals  there  must  be  a 
medium  capable  of  absorbing  it.  There  were  thoughtful 
men,  however,  who  would  not  be  satisfied  with  explanations 
of  this  kind.  Boerhaave,  whose  Elementa  Chemiae  (1732) 
served  for  many  years  as  the  standard  text-book  of  chem- 
istry, taught  distinctly  that  the  conversion  of  metals  into 
calces  involved  the  absorption  of  something  from  the  air. 
This  he  deduced  by  combining  the  fact  that  the  presence  of 
air  was  necessary  with  the  fact  that  the  conversion  involved 
increase  in  weight.  The  latter  fact  he  even  freed  from  an 
erroneous  explanation  attached  to  it  by  Boyle,  who  had 
thought  that  the  increase  in  weight  was  due  to  the  absorp- 
tion of  heat  during  calcination.  By  the  use  of  the  balance 
Boerhaave  showed  that  metals  have  precisely  the  same 
weight  when  glowing  hot  as  when  cold,  and  thus  proved 
that  heat  has  no  weight.  So  near  the  truth  were  some. 
Yet  none  rose  to  combat  the  phlogistic  theory,  and  all- 
even  Boerhaave — were  dominated  by  it  more  or  less. 

Two  things  were  necessary  to  make  away  with  phlogiston : 
First,  a  clear  knowledge  of  some  of  the  ordinary  gases; 
second,  a  clear  quantitative  knowledge  of  some  of  the 
ordinary  chemical  transformations.  The  gases  in  question 
are  carbon  dioxide,  oxygen  and  air.  As  to  quantitative 
chemical  knowledge,  it  can,  of  course,  be  acquired  ulti- 
mately only  by  the  use  of  the  balance.  Carbon  dioxide 
(called  "carbonic  acid")  was  known  since  the  time  of  Van 
Helmont;  yet  chemists  were  not  sure  but  that  it  might  be 
impure  air,  until  Joseph  Black  isolated  it  and  demonstrated 
its  properties  in  1755.  Bergman  completed  the  study  of  this 
gas  in  1774.  The  presence  and  properties  of  oxygen  were 


CHEMISTRY  AND  ITS  DEVELOPMENT       213 

suspected  by  Boyle,  Mayow  (1669),  Boerhaave  and  others; 
but  it  was  first  actually  isolated  by  Priestley  and  Scheele 
in  1774.  The  nitrogen  of  the  air  was  isolated  by  Ruther- 
ford in  1772.  It  must  be  remarked  here  that  the  apparatus 
and  manipulations  of  "pneumatic  chemistry"  were  grad- 
ually perfected  by  Boyle,  Hales,  Moitrel  d 'Element,  Black 
and  Priestley  (the  latter  having  invented  the  method  of 
collecting  gases  over  mercury),  which  rendered  possible 
the  isolation  of  gases  that  are  soluble  in  water.  But  the 
precise  demonstration  of  the  composition  of  gases  and  the 
introduction  of  the  systematic  use  of  the  balance  are  due 
to  the  founder  of  quantitative  chemistry,  the  French 
physician  and  chemist  Lavoisier. 

,  But  before  we  proceed  to  further  narrate  the  progress 
of  chemical  philosophy,  it  remains  to  enumerate  briefly  the 
achievements  of  chemical  technology  during  the  reign  of 
phlogiston.  In  spite  of  this  fundamental  error,  chemistry 
was  making  fairly  rapid  progress,  and  this  naturally  told 
on  the  industries.  Boyle  and  Kunkel  improved  many 
metallugical  processes  and  the  manufacture  of  glass.  The 
manufacture  of  iron  and  steel  owed  valuable  improvements 
to  the  researches  of  Bergman,  Gahn,  Rinman  and  Reaumur. 
Stahl,  Scheele,  Hellot,  Macquer  and  others  introduced  new 
dyestuffs  and  improved  many  processes  of  dyeing.  The 
preparation  of  zinc  was  improved  by  Marggraff  and  its 
manufacture  on  a  large  scale  was  commenced  at  Bristol  in 
1743.  The  manufacture  of  sulphuric  acid  was  commenced 
by  Ward  at  Richmond;  and  in  1746  lead  chambers  were 
first  introduced  by  Roebuck.  In  1747  Marggraff  dis- 
covered sugar  in  beets ;  the  sugar  industry,  however,  was  not 
born  until  the  beginning  of  the  nineteenth  century.  Early 
in  the  eighteeth  century  (1703)  Bottger  was  accidentally 
led  to  the  invention  of  porcelain,  and  its  manufacture 
commenced  at  Meissen  in  1710:  but  the  process  was  kept 
secret,  and  the  manufacture  was  confined  to  Meissen  until 
Reaumur  rediscovered  it  by  systematic  research,  and  finally, 
in  1769,  great  porcelain  works  were  established  at  Sevres, 


214  MODERN  SCIENCE  READER 

near  Paris.  In  the  course  of  the  period  many  substances 
were  introduced  a§  therapeutic  agents,  and  Scheele  dis- 
covered a  number  of  important  compounds  of  carbon. 

If,  after  we  have  become  accustomed  to  think  of  modern 
chemistry  as  founded  in  the  latter  part  of  the  eighteenth 
century,  we  take  up  the  writings  of  phlogistic  chemists  prior 
to  that  time,  we  may  be  greatly  surprised  to  find  that  our 
general  principles  were  not  at  all  unknown  to  them.  They 
certainly  believed  in  the  indestructibility  of  matter,  and 
some  of  them  described  molecules  and  atoms  in  much  the 
same  way  as  we  describe  them  at  the  present  day.  And 
yet  their  knowledge  cannot  be  rightly  considered  as  consti- 
tuting a  science.  Their  abstract  speculations  were  very 
keen;  their  knowledge  of  chemical  facts  was  quite  ex- 
tensive; but  that  mathematical  correspondence  between 
abstract  principles  and  concrete  phenomena  which  alone 
constitutes  science  did  not  exist.  And  so,  even  when  the 
properties  of  gases  were  no  longer  unknown,  all  chemical 
knowledge  remained  in  a  state  of  confusion,  and  elements 
continued  to  be  considered  as  compounds,  compounds  as 
elements,  combinations  as  decompositions,  and  decomposi- 
tions as  combinations,  until  the  work  of  establishing  the 
scientific  correspondence  was  begun  by  Lavoisier. 

Endowed  by  nature  with  a  keenly  critical  mind,  Lavoisier 
acquired  the  habit  of  quantitative  thinking  by  early  train- 
ing in  mathematics  and  physics,  and  by  subsequent  associa- 
tion with  some  of  the  most  brilliant  mathematicians  and 
physicists  of  his  time.  As  early  as  1770  we  find  him  solv- 
ing a  problem  of  chemistry  by  a  purely  quantitative 
method.  It  was  known,  namely,  that  when  water  is  kept 
boiling  for  some  time  in  a  glass  vessel,  there  is  formed  in 
it  an  earthy  deposit;  it  was  therefore  believed  that  water 
could  be  converted  into  "earth".  Lavoisier  heated  water 
in  a  glass  vessel,  weighed  the  vessel  before  and  after  the 
operation,  and  found  that  the  vessel  plus  the  deposit  after 
the  operation  weighed  exactly  as  much  as  the  vessel  alone 
weighed  before.  He  thus  proved  that  the  earthy  deposit 


CHEMISTRY  AND  ITS  DEVELOPMENT      215 

came,  not  from  the  water,  but  from  the  glass  of  the  vessel. 
In  1772  he  turned  the  same  quantitative  method  of  experi- 
menting and  reasoning  to  the  conversion  of  metals  into 
calces,  and  in  1774  published  the  following  observation: 
' '  When  metallic  tin  is  heated  in  a  sealed  retort  full  of  air, 
it  becomes  transformed  into  its  calx;  the  weight  of  the 
sealed  retort  with  its  contents  is  exactly  the  same  after  the 
reaction  as  before;  if  the  retort  is  now  opened,  air  rushes 
into  it  and  the  weight  is  increased;  the  increase  is  equal 
to  the  difference  in  weight  between  the  calx  formed  and 
the  mass  of  metallic  tin  employed."  From  this  Lavoisier 
concluded  that  the  transformation  of  tin  into  its  calx  in- 
volved the  absorption  of  air,  and  that  phlogiston  had  noth- 
ing to  do  with  the  phenomenon.  It  also  became  evident  to 
him  that  the  balance  of  precision  could  serve  the  chemist 
no  less  than  the  telescope  served  the  astronomer,  and  that 
the  principle  of  indestructibility,  which  could  and  should 
be  established  experimentally,  ought  to  be  at  the  basis  of 
all  chemical  reasoning.  When  Priestley  and  Scheele  dis- 
covered oxygen,  they  thought  that  it  was  this  constituent 
of  air  that  was  capable  of  absorbing  phlogiston  from  metals ; 
Lavoisier  demonstrated  that  it  was  this  constituent  of  air 
that  combined  with  metals  to  form  calces.  He  recognized 
that  the  same  gas  combined  with  sulphur,  phosphorus,  char- 
coal and  other  combustible  substances  and  as  he  regarded 
the  resulting  compounds  as  acids,  he  gave  to  the  gas  the 
name  oxygen  (from  the  Greek  oxys,  acid,  and  genes,  pro- 
ducing), and  adopted  the  view  that  it  was  an  indispensable 
constituent  of  all  acids  (this  view  was  discarded  half  a 
century  later).  Carbonic  acid  he  recognized  as  a  com- 
pound of  carbon  and  oxygen,  and  when  Cavendish  found 
that  the  sole  product  of  the  combustion  of  hydrogen  in 
oxygen  was  water,  Lavoisier  understood  that  water  was  not 
an  element,  but  a  compound  of  hydrogen  and  oxygen,  and 
had  no  difficulty  in  determining  its  quantitative  composi- 
tion. Carbonic  acid  and  water  he  also  showed  to  be  the 
products  of  the  combustion  of  organic  substances,  and  soon 


216  MODERN  SCIENCE  READER 

he  recognized  that  respiration  too,  was  a  process  of  organic 
combustion. 

Logical  and  consistent  as  Lavoisier's  method  appears  to 
the  unprejudiced  mind,  it  failed  to  appeal  to  some  of  the 
most  eminent  men  of  his  time.  Thoroughly  accustomed  to 
the  inverted  principles  of  the  phlogistic  doctrine,  those 
men  adhered  to  them  as  firmly  as  fanatics  will  adhere  to 
an  absurd  creed,  and  some  of  them,  including  Priestley, 
himself  the  discoverer  of  oxygen,  died  believers  in  phlo- 
giston. Nevertheless,  Lavoisier  lived  to  see  the  light  of 
his  system  spread  over  the  entire  scientific  world,  and  turn 
chaos  into  order.  He  had  established  a  rigid  correspond- 
ence between  the  law  of  indestructibility  and  chemical 
transformations,  and  had  thus  built  the  first  bridge  between 
an  abstract  principle  and  the  world  of  chemical  phenomena. 
The  concept  element  was  now  correctly  applied  to  oxygen, 
hydrogen,  carbon,  sulphur,  phosphorus  and  the  metals  then 
known  in  the  free  state;  the  concept  compound  was  cor- 
rectly applied  to  water  and  the  oxides  of  the  metals.  True 
enough,  in  his  list  of  elements  (1787)  Lavoisier  included 
also  light  and  heat  and  the  compounds  potash,  soda  and 
lime;  while,  on  the  other  hand,  he  considered  the  element 
chlorine  as  a  compound  containing  oxygen.  But  this  did 
not  interfere  with  further  progress.  The  first  bridge  of 
chemistry  was  firmly  established,  and  the  lingering  errors 
were  rectified  (mainly  by  Sir  Humphry  Davy)  early  in 
the  nineteenth  century.  The  development  of  another  cor- 
respondence—viz :  that  between  the  hypothesis  of  the 
atomic  constitution  of  matter  and  the  quantitative  composi- 
tion of  substances— has  been  already  noted  in  a  preceding 
section  of  this  article.  Here  it  may  be  observed  that  the 
law  of  multiple  proportions  was  first  discovered  by  Richter 
(1762-1807),  and  that  Proust  (1754-1826)  continued  Rich- 
ter's  researches  and  clearly  demonstrated  the  law  in  course 
of  a  controversy  with  Berthollet.  Dalton  (1804)  re-dis- 
covered the  law  deductively  and  then  proved  it  experimen- 
tally ;  he  was  thus  the  first  to  establish  a  rational  connection 


CHEMISTRY  AND  ITS  DEVELOPMENT      217 

between  the  old  atomic  hypothesis  and  the  facts  of  chemical 
composition. 

After  the  relation  between  the  known  metals  and  their 
oxides  was  established,  Lavoisier  himself,  and  others,  be- 
gan to  suspect  the  true  nature  even  of  oxides  whose  metals 
were  not  yet  known  in  the  free  state,  and  attempts  began 
to  be  made  to  decompose  these  oxides  so  as  to  isolate  their 
metallic  elements.  About  the  beginning  of  the  nineteenth 
century,  Sir  Humphry  Davy  (1778-1829)  undertook  to 
investigate  the  effect  of  the  galvanic  current  on  chemical 
compounds.  In  1807-08  he  succeeded  in  decomposing 
caustic  potash  and  caustic  soda,  obtaining  from  them  the 
metals  potassium  and  sodium. 

About  the  same  time  Seebeck  similarly  decomposed  the 
oxides  of  calcium,  barium,  strontium  and  magnesium, 
obtaining  these  metals  in  the  form  of  their  amalgams — i.e. 
combinations  with  mercury.  From  these  amalgams  Davy 
isolated  the  metals  themselves  and  gave  them  their  present 
names.  From  the  metals  Davy  turned  his  genius  to  the 
non-metallic  elements.  Chlorine,  known  since  1774,  re- 
mained unrecognized  as  an  element,  and  was  generally  con- 
sidered as  the  oxide  of  hydrochloric  acid.  In  1811  Davy 
clearly  demonstrated  its  elementary  nature ;  and  when, 
soon  afterwards,  Courtois  discovered  iodine,  Davy  showed 
that  this  substance,  too,  so  similar  to  chlorine,  must  be  con- 
sidered as  an  element.  Davy  also  was  the  first  to  demon- 
strate clearly  the  elementary  nature  of  nitrogen  and  even 
of  fluorine  (from  the  similarity  of  hydrofluoric  to  hydro- 
chloric acid,  and  of  the  fluorides  to  the  chlorides),  although 
the  latter  element  was  not  then  known  in  the  free  state, 
and  remained  unknown  until  1887.  The  value  of  Davy's 
contributions  can  be  readily  appreciated  if  we  remember 
that  the  substances  he  was  dealing  with  are  among  the 
commonest  in  the  entire  range  of  chemistry,  and  if  we 
imagine  how  much  confusion  would  suddenly  ensue  in  all 
departments  of  the  science  if  we  were  to  forget  their  exist- 
ence or  their  true  nature. 


218  MODERN  SCIENCE  READER 

DUALISM.  On  the  basis  of  his  electrolytic  investigations 
Davy  also  constructed  an  electro-chemical  theory  which 
was  subsequently  modified  and  extended  by  Berzelius. 
According  to  Davy  (1807)  when  the  atoms  of  different  ele- 
ments come  into  contact,  they  become  charged  with  the 
opposite  forms  of  electricity,  by  whose  attractive  force  they 
are  held  together,  constituting  chemical  compounds.  Ber- 
zelius' theory  was  as  follows:  "The  atom  of  each  element 
does  not  become  charged  with  electricity  on  coming  in  con- 
tact with  other  atoms,  but  is  charged,  whether  combined 
with  other  atoms  or  not.  With  respect  to  the  electrical 
charges  of  their  atoms,  the  elements  form  an  'electro-chem- 
ical order,'  oxygen  being  about  the  most  electro-negative, 
potassium  the  most  electro-positive  of  elements.  All  bases 
are  produced  by  the  combination  of  oxygen  with  electro- 
positive elements  and  all  acids  by  the  combination  of 
oxygen  with  electro-negative  elements.  Yet  bases  and  acids 
are  not  altogether  neutral,  in  the  former  positive  electricity, 
in  the  latter  negative  electricity,  predominates.  This  is 
why  bases  and  acids  show  no  mutual  chemical  indifference, 
but  combine  to  form  salts.  When  the  terminals  of  a  suf- 
ficiently powerful  galvanic  battery  are  immersed  in  the 
solution  of  a  salt,  the  base  of  the  latter  is  attracted  more 
strongly  by  the  negative  terminal  than  by  the  acid;  and 
the  acid  is  attracted  more  strongly  by  the  positive  terminal 
than  by  the  base;  hence  electrolysis  ensues,  the  base  being 
deposited  on  the  negative,  the  acid  on  the  positive,  term- 
inal." In  brief,  Berzelius  maintained  (1)  that  oxygen  is 
an  indispensable  constituent  of  bases,  acids  and  salts;  (2) 
that  bases,  acids  and  salts  have  a  dual  constitution,  each 
being  made  up  of  an  electro-positive  and  an  electro-nega- 
tive part;  (3)  that  chemical  affinity  is  nothing  but  the 
mutual  attraction  of  opposite  forms  of  electricity.  In  the 
first  of  these  principles  Berzelius  followed  Lavoisier,  for 
years  refusing  to  accept  Davy's  view  that  chlorine  and 
nitrogen  were  elements,  and  that  their  compounds  with 
hydrogen— namely  hydrochloric  acid  and  ammonia— al- 


CHEMISTRY  AND  ITS  DEVELOPMENT      219 

though  respectively  an  acid  and  a  base,  contained  no 
oxygen.  The  structure  of  the  entire  theory  became  some- 
what shaky  when  the  correctness  of  Davy's  views  was 
finally  recognized  by  all,  including  Berzelius  himself 
(1820).  Nevertheless,  Berzelius,  and  with  him  the  entire 
chemical  world,  continued  to  adhere  to  the  electro-chemical 
theory,  and  thus  a  strictly  dualistic  conception  of  com- 
pounds continued  to  reign  in  the  science.  The  thirties, 
however,  brought  much  new  evidence  against  Berzelius' 
principles.  First  of  all  it  was  recognized  that  electrolysis 
breaks  up  a  salt,  primarily  not  into  two  oxides,  but  into  a 
free  metal  and  an  acid  radicle.  For  example,  potassium 
sulphate  is  broken  up,  primarily,  not  into  K20  and  S03, 
but  into  2K  and  the  radicle  S04.  This  made  it  evident 
that  sulphuric  acid  was  not  S03,  but  H2S04  (i.e.  S03  chem- 
ically combined  with  H20),  because  the  S04  radicle  was 
seen  to  be  the  true  acidic  component  of  potassium  sulphate. 
Two  important  conclusions  thus  thrust  themselves  upon 
chemists:  (1)  An  acid  is  not  a  binary  compound  of  oxygen 
with  an  electro-negative  element,  but  a  combination  of 
hydrogen  with  an  electro-negative  radicle;  (2)  a  salt  is  not 
a  compound  of  two  oxides  (e.g.  K2O.S03)  but  a  combination 
of  a  metallic  element  with  the  electro-negative  radicle 
(e.g.  S04)  of  an  acid.  The  first  of  these  conclusions,  to- 
gether with  Davy's  discovery  that  hydrochloric  acid  con- 
tained hydrogen  but  no  oxygen,  indicated  that  not  oxygen, 
but  hydrogen,  is  an  indispensable  component  of  acids,  and 
this  vie:v  was  further  strengthened  by  Graham's  and 
Liebig's  classical  studies  of  the  so-called  polybasic  acids. 
But  so  profound  was  Berzelius'  belief  in  dualism,  and  so 
great  was  his  authority,  that  the  electro-chemical  theory 
still  continued  to  stand,  and  the  conclusions  just  pointed 
out  were  not  generally  accepted  for  some  years.  The  final 
blow  to  dualism  came  from  the  young  organic  chemistry, 
in  which  the  electric  theory  had  been  applied  as  generally 
as  in  the  inorganic  branch  of  the  science.  About  the  middle 
of  the  thirties  Laurent  and  Dumas  made  a  series  of  im- 


220  MODERN  SCIENCE  READER 

portant  discoveries  showing  that  chlorine  and  other  ele- 
ments could  be  substituted  for  the  hydrogen  or  organic 
compounds,  and  that  the  nature  of  the  latter  was  thereby 
affected  very  little.     But  if  part  of  the  molecule  of  a  com- 
pound can  combine  with  either  of  such  electrically  different 
atoms  as  those  of  hydrogen  and  of  chlorine,  then  there  is 
no  reason  for  believing  that  that  part  is  essentially  either 
electro-positive  or  electro-negative,  and  hence  there  is  no 
reason  for  believing  that  every  compound  is  made  up  of 
two  electrically  opposite  parts.     The  more  evidence  to  this 
effect  was  brought  forward,  the  more  bitterly  old  Berzelius 
adhered  to  the  electro-chemical  theory.     But  finally  it  be- 
came evident  to  all  that,  as  Liebig  wrote,  "the  wheel  of 
time  cannot  stand  still,"  and  "Berzelius  is  fighting  for  a 
lost  cause ' ' ;  and,  thus  toward  the  end  of  the  thirties,  elec- 
tro-chemical dualism  was  overthrown.     As  a  result  of  their 
struggles  against  dualism,  chemists  then  fell  into  the  oppo- 
site extreme  and  adopted  a  purely  unitary  view  of  chemical 
combination.     The  molecule  of  a  compound  was  conceived 
to  be  a  composite  unit  somewhat  like  the  solar  system,  in 
which  the  planets  are  held  together  by  mutual  attraction, 
but  which  does  not  by  any  means  consist  of  two  essentially 
different  parts,  endowed  with  two  opposite  forms  of  energy. 
Such  unitary  views  of  combination  are  still  prevalent  in 
chemistry  to-day.     But  "the  wheel  of  time  cannot  stand 
still,"  and  recent  years  have  forced  upon  us  theories  which 
make  us  feel  that  extreme  unitarism  is  just  as  inadequate 
as  extreme  dualism.     The  elements  certainly  differ  in  their 
electrical  properties,  and  chemists  have  even  succeeded  now 
in  expressing  those  differences  mathematically.   Electricity, 
while  not  identical  with  the  energy  that  causes  the  mutual 
attraction   of   atoms,   is   yet   certainly   one   of   the   factors 
determining  that   attraction.     At   present,   however,   it   is 
impossible  to  tell  what  compromise  between  chemical  unita- 
rism and  electro-chemical  unitarism  and  electro-chemical 
dualism  will  ultimately  be  adopted. 

ORGANIC  CHEMISTRY.    When  the  general  principles  of 


CHEMISTRY  AND  ITS  DEVELOPMENT      221 

chemistry  were  established,  and  the  atomic  hypothesis  had 
lent  to  the  science  a  keen  power  of  penetration,  it  became 
possible  to  approach  the  world  of  organic  matter  with  the 
hope  of  shedding  some  light  upon  its  mystery.  Since  then 
organic  research  occupied  chemists  almost  exclusively  dur- 
ing a  greater  part  of  the  nineteenth  century,  and  the  result 
of  that  inquiry  has  been  not  only  a  vast  store  of  empirical 
knowledge  of  organic  compounds,  but  also  a  set  of  general 
principles  that  have  strengthened  the  theoretical  basis  of 
the  science,  and  have  led  to  some  of  the  great  industrial 
achievements  of  modern  times. 

Early  in  the  nineteenth  century  it  was  universally  be- 
lieved that  organic  substances  could  not  be  produced  with- 
out the  agency  of  the  "force  of  life."  Whether  there  is 
such  a  distinct  "force"  and  what  its  relations  may  be  to 
the  measurable  forms  of  energy,  we  do  not. know  as  yet. 
But  we  do  know  that  organic  compounds  can  also  be  pro- 
duced by  chemical  agencies  alone,  without  the  intervention 
of  anything  else.  For  chemists  have  actually  succeeded  in 
building  up  from  their  elements  many  thousands  of  com- 
pounds that  occur  ready  formed  only  in  the  organisms  of 
animals  and  plants.  The  first  of  such  compounds  repro- 
duced in  the  laboratory  was  urea,  which  Wohler  made  arti- 
ficially in  1828.  The  old  belief,  however,  lingered,  some 
chemists  contending  that  urea  could  not  be  looked  upon  as 
a  true  organic  compound.  But  when  Kolbe  synthesized 
acetic  acid  in  1845,  and  when  other  indisputably  organic 
compounds  were  made  from  their  elements,  then  all  agreed 
that  there  was  no  essential  difference  between  organic  and 
inorganic  compounds,  and  that  the  former  were  nothing 
but  the  compounds  of  carbon.  At  present  many  dye  stuffs, 
drugs  and  perfumes,  which  could  once  be  obtained  only 
from  plants,  are  made  artificially  on  a  large  scale,  and  so 
are  many  valuable  carbon  compounds  that  are  not  known 
to  occur  ready  formed  at  all. 

While  the  belief  in  an  indispensable  force  of  life  thus 
delayed  for  a  time  the  progress  of  chemical  synthesis, 


222  MODERN  SCIENCE  READER 

chemists  early  directed  their  attention  to  the  problem  of 
molecular  constitution.  Berzelius  was  led  to  this  problem 
by  his  electro-chemical  theory.  But  in  the  twenties  facts 
became  known  which  made  its  study  an  imperative  necessity 
also  from  a  purely  practical  standpoint.  Not  small  was 
the  surprise  of  chemists  when  Gay-Lussac  and  Liebig  found, 
in  1823,  that  silver  fulminate  had  precisely  the  same  com- 
position as  silver  cyanate.  Two  years  later,  Faraday  dis- 
covered a  volatile  liquid  hydrocarbon  that  had  precisely 
the  same  composition  as  ethylene  gas.  Berzelius  first 
thought  it  unwise  to  abolish,  on  the  evidence  of  a  few  facts, 
what  had  seemed  an  axiom— viz.  that  two  different  com- 
pounds cannot  possibly  have  the  same  composition.  But 
when  he  discovered  that  racemic  and  tartaric  acids,  too,  had 
the  same  composition,  he  realized  that  the  character  of  a 
substance  must  depend  not  only  on  its  composition,  but  also 
on  its  constitution— i.e.,  not  only  on  the  kind  and  number, 
but  also  on  the  arrangement  of  the  atoms  in  its  molecule. 
Thus  was  born  that  great  problem  of  modern  chemistry— 
to  determine  the  constitution  of  substances  from  the  stand- 
point of  the  atomic  hypothesis. 

In  1832  Liebig  and  Wohler  made  an  important  discovery. 
A  series  of  compounds  allied  to  benzoic  acid  were  trans- 
formed by  them  into  one  another,  and  through  all  the  trans- 
formations a  group  of  atoms  (made  up  of  carbon,  hydro- 
gen, and  oxygen)  which  they  named  the  "benzoyl  radicle" 
remained  unchanged ;  the  molecules  of  benzoic  acid,  benzal- 
dehyde,  benzamide,  and  benzoyl  chloride,  contained  that 
radicle  in  common,  as  if  it  were  a  single  atom  of  some  ele- 
ment. The  discovery  of  benzoyl  was  followed  by  Liebig 's 
discovery  of  ethyl,  a  radicle  common  to  ordinary  alcohol 
and  ether,  and  by  Bunsen's  discovery  of  cacodyl,  which  is 
possessed  in  common  by  several  compounds  of  arsenic.  The 
discovery  of  radicles  was  obviously  the  first  step  toward  a 
knowledge  of  the  constitution  of  compounds.  But  almost 
from  the  beginning  the  idea  of  radicles  became  associated 
with  certain  other  ideas  that  could  not  be  maintained  in 


CHEMISTRY  AND  ITS  DEVELOPMENT      223 

the  light  of  more  knowledge.  Berzelius  subdivided  organic 
radicles,  like  the  elements,  into  electro-positive  and  electro- 
negative. On  the  other  hand,  it  was  generally  expected 
that  radicles  would  eventually  be  isolated  and  thus  consti- 
tute a  series  of  simple  compounds  whose  molecules  would 
bear  the  same  relation  to  the  substances  of  organic  chem- 
istry as  the  atoms  of  the  elements  bear  to  the  compounds  of 
inorganic  chemistry.  But  when  the  electro-chemical  theory 
was  overthrown,  while  attempts  to  isolate  radicles  remained 
fruitless,  the  opinion  began  to  spread  that  the  theory  of 
radicles  had  made  of  organic  chemistry  a  science  of  imagi- 
nary substances,  and,  hence,  the  sooner  the  theory  was 
abolished  the  better  for  the  young  science.  But  how,  then, 
were  organic  compounds  to  be  correlated?  A  solution  of 
this  problem  was  suggested  by  Dumas  in  1839.  Continuing 
his  researches  on  the  substitution  of  different  elements  for 
one  another  in  organic  compounds,  Dumas  found  that  in 
acetic  acid  hydrogen  could  be  exchanged  for  chlorine,  and 
that  the  resulting  compound  (trichlor-acetic  acid)  was  very 
much  like  acetic  acid  itself.  Similar  facts  had  already  been 
observed  since  1834,  by  himself  as  well  as  by  Laurent.  It 
now  occurred  to  Dumas  that  in  correlating  their  substances 
chemists  could  be  guided  solely  by  the  phenomena  of  sub- 
stitution. Acetic  acid  and  its  chlorine-substitution  product 
obviously  belong  to  the  same  ''type,"  and  similar  relations 
exist  between  other  substances  as  well.  If,  therefore,  the 
phenomena  of  substitution  were  investigated  in  connection 
with  organic  compounds  in  general,  the  result  would  be  a 
grouping  of  compounds  free  from  all  hypothesis,  but  based 
on  and  exhibiting  clearly  their  natural  relationship.  Such 
were,  in  nuce,  Dumas'  views,  on  the  basis  of  which  the 
celebrated  * '  theory  of  types ' '  was  gradually  built  up  •  in 
course  of  the  fourth  and  fifth  decades.  The  most  impor- 
tant contributions  to  the  theory  were  made  by  Gerhardt, 
Wurtz,  Hofmann,  and  Williamson.  Gerhardt  realized  that 
Dumas'  ideas  were  worthy  of  being  developed,  but  he  also 
realized  that  this  could  not  be  done  without  the  aid  of  the 


224  MODERN  SCIENCE  READER 

idea  of  radicles.  No  objection  could  be  raised  against  the 
latter  idea,  once  it  were  freed  from  all  unnecessary  assoc;a- 
tions,  especially  from  the  belief  that  radicles  were  unalter- 
able substances  capable  of  independent  existence.  To  say 
that  benzoyl  chloride  C7H5OC1 ;  benzoic  acid,  C7H602 ;  and 
benzamide,  C7H7ON,  contain  in  common  the  benzoyl  radi- 
cle—i.e.  the  group  of  atoms,  C7H50— was  only  to  express 
what  was  evident  from  their  formulae.  On  the  other  hand, 
the  recognition  of  radicles  must  obviously  lead  to  the  dis- 
covery of  the  relationship  of  compounds,  and  thus,  together 
with  the  phenomena  of  substitution,  guide  in  grouping 
compounds  in  accordance  with  the  idea  of  types.  In  1849 
Wurtz  and  Hofmann  discovered  a  series  of  compounds  that 
bore  an  unmistakable  resemblance  to  ordinary  ammonia, 
and  could  be  considered  as  ammonia  in  which  one  or  more 
hydrogen  atoms  were  replaced  by  radicles.  They  proposed 
to  group  them  together  as  belonging  to  the  "ammonia 
type."  In  1850  Williamson  showed  that  alcohols,  ethers, 
and  acids  could  be  referred  to  the  "water  type."  Ordinary 
alcohol,  for  instance,  whose  formula  is  C2H60,  could  be  con- 
sidered as  water,  H20,  in  which  one  hydrogen  atom  has  been 
replaced  by  the  ethyl  radicle,  C2H5.  Ordinary  ether, 
C4H100,  could  be  considered  as  water,  H20,  in  which  two 
hydrogen  atoms  have  been  replaced  by  two  ethyl  radicles, 
ether  being  thus  (C2H5)20.  Acetic  acid  C2H402  could  be 
considered  as  water,  H20,  in  which  one  hydrogen  atom  has 
been  replaced  by  the  radicle  C2H30.  Now,  ether,  (C2H5)20 
was  obtained  from  alcohol  C2H5HO,  by  the  use  of  dehydrat- 
ing agents.  Williamson  therefore  held,  by  analogy,  that  it 
ought  to  be  possible  to  transform  acetic  acid,  C2H3O.HO 
into  a  compound  (C2H30)20.  When  in  1852,  Frankland 
actually  succeeded  in  effecting  this  transformation  by  the 
use  of  dehydrating  agents,  the  usefulness  of  the  type 
theory  was  demonstrated.  For  nothing  is  more  striking 
proof  of  the  value  of  a  theory  than  its  capacity  for  reveal- 
ing unknown  facts.  To  the  types  ammonia  and  water 
Gerhardt  added  the  types  hydrogen  and  h3Tdrochloric  acid, 


CHEMISTRY  AND  ITS  DEVELOPMENT      225 

and  for  a  time  it  seemed  that  all  organic  compounds  could 
be  grouped  under  these  four  simple  types.  It  was  soon, 
found  necessary,  however,  to  introduce  the  ideas  of  "  con- 
densed types"  like  the  condensed  water  type  (H20)2, 
" mixed  types"  and  the  type  marsh  gas,  CH4.  In  the 
course  of  the  fifties  the  type  theory  thus  gradually  became 
less  and  less  simple,  and,  hence,  less  and  less  valuable  for 
the  purpose  of  correlating  organic  compounds. 

Meanwhile  an  idea  of  inestimable  value  had  thrust  itself 
upon  chemists.  Inspecting  the  typical  formulas  of  com- 
pounds, they  could  not  help  noticing  that  certain  radicles 
(e.g.  methyl,  CH3,  or  ethyl,  C2H5)  were  capable  of  replac- 
ing each  a  single  atom  of  hydrogen;  others  were  capable 
of  replacing  each  two  atoms  of  hydrogen,  etc.  In  other 
words,  some  radicles  were  seen  to  be  equivalent  to  an  atom 
of  hydrogen ;  others  had  double  its  combining  capacity, 
etc.  Hence  the  idea  of  the  valency  of  radicles  and  atoms. 
Like  most  other  general  ideas,  that  of  valency  was  not  new. 
In  a  vague  and  more  or  less  specialized  form  it  may  be 
found  in  the  researches  of  Berzelius,  Graham,  Liebig,  and 
others ;  and  Frankland,  who  first  clearly  enunciated  it,  in 
1852,  justly  points  out  that  it  was  probably  a  vague  recog- 
nition of  the  valency  of  radicles,  as  exhibited  by  the  facts 
of  substitution,  that  gave  birth  to  the  theory  of  types. 
Frankland 's  statements,  however,  attracted  no  attention. 
In  1858  Kekule  and  Couper  independently  developed  the 
same  idea,  the  latter  proposing  to  symbolize  the  combining 
capacity  of  different  atoms  by  the  dashes  now  generally 
employed  in  graphic  formulae.  Kekule  called  attention  to 
the  quadrivalence  of  the  carbon  atom,  as  shown  directly  by 
compounds  like  the  following:  CH4,  CH3C1,  CH2C12, 
CHC13,  CC14 ;  or  indirectly  by  such  compounds  as  C02, 
COC12.  In  the  former  compounds  a  single  atom  of  carbon 
is  seen  to  be  equivalent  to  four  atoms  of  hydrogen,  and  a 
single  chlorine  atom  to  a  single  atom  of  hydrogen,  which  is 
also  shown  by  the  formula  of  hydrochloric  acid,  HC1,  In 
a  compound  like  COC12,  the  oxygen  atom  must  therefore 
15 


226  MODERN  SCIENCE  READER 

be  assumed  to  be  divalent,  and  so  it  is  directly  shown  to  be 
by  the  formula  H20.  Kekule  soon  came  to  the  conclusion 
that  in  practically  all  organic  compounds  one  carbon  atom 
is  combined  with  a  quantity  of  other  elements  which  is 
equivalent  to  four  atoms  of  hydrogen.  This  gave  rise  to  a 
lively  controversy,  the  critic  Kolbe  especially  maintaining 
that  the  valency  of  an  element  may  not  be  the  same  in  all 
of  its  compounds.  Kekule 's  view,  however,  was  finally 
accepted  by  all,  and  in  1860  chemists  the  world  over  were 
busy  determining  the  "structure"  of  organic  compounds— 
a  problem  which  has  since  occupied  the  attention  of  a 
majority  of  them  almost  exclusively.  The  theory  of  types, 
the  mother  of  structural  theory,  exhibited  the  radicles  of 
compounds,  and  thus  explained  those  cases  of  isomerism  in 
which  compounds  are  different  because  they  contain  differ- 
ent radicles.  Those  further  cases  in  which  the  radicles 
themselves  are  differently  constituted  it  could  not  explain. 
The  doctrine  of  valency,  showing  the  different  ways  in 
which  the  atoms  can  be  linked  in  the  radicles,  has  furnished 
a  satisfactory  solution  of  the  problem  of  molecular  consti- 
tution, and  has  completely  explained  the  fact  that  the 
molecules  of  different  compounds  may  be  made  up  of  the 
same  atoms.  At  first  Kekule  failed  to  appreciate  the  full 
value  of  his  own  ideas.  In  the  very  memoir  in  which  he 
states  the  doctrine  of  valency,  he  advances  the  view  that 
this  doctrine  cannot  by  any  means  solve  the  problem  of  the 
constitution  of  compounds;  the  old  problem,  he  thought, 
might  possibly  be  solved  some  day  by  physical  chemistry. 
Perhaps  he  was  not  altogether  wrong.  For  now,  after  half 
a  century  of  experience,  organic  chemists  are  beginning  to 
complain  of  the  inadequacy  of  the  structural  theory,  even 
with  its  more  recent  development— stereochemistry  (q.v.)  — 
and  to  look  forward  to  some  broader  idea,  that  would  cor- 
relate a  larger  number  of  known  phenomena  and  permit 
of  foreseeing  a  larger  number  of  as  yet  unknown  facts. 
What  that  idea  -will  be,  no  one  can  tell  as  yet. 

GENERAL  CHEMISTRY.     The  doctrine  of  valency  could  not 


CHEMISTRY  AND  ITS  DEVELOPMENT      227 

have  come  into  existence  if  not  for  the  fact  that  toward  the 
end  of  the  fifties  chemists  had  learned  the  true  atomic 
weights  of  the  elements.  Without  a  knowledge  of  the  true 
relative  weights  of  atoms,  it  would  have  been  impossible  to 
know  their  true  number  in  molecules,  and,  hence,  impossible 
to  know  their  true  valencies.  Atomic  weights  were  deter- 
mined, calculated,  and  re-calculated  ever  since  Dalton  first 
established  the  atomic  theory.  Dalton  himself,  as  stated 
in  a  previous  section  of  this  article,  determined  atomic 
weights  on  the  basis  of  certain  simple  assumptions.  Soon 
afterward  Berzelius  devoted  himself  to  the  problem  with 
great  assiduity.  From  the  law  of  combining  volumes,  dis- 
covered by  Gay-Lussac  in  1808,  Berzelius  inferred  that 
equal  volumes  of  gaseous  elements  must  contain  equal 
numbers  of  particles.  In  1819  Mitscherlich  discovered  the 
principle  of  isomorphism.  (See  Atomic  Weights.)1  Ber- 
zelius had  carried  out  about  two  thousand  analyses,  and 
had  thus  determined  the  relative  quantities  of  the  elements 
contained  in  a  great  variety  of  compounds.  By  combining 
the  principle  of  isomorphism  with  that  of  equal  gaseous 
volumes,  he  was  now  able  to  calculate  the  atomic  weights 
of  the  elements.  Now,  his  principle  of  equal  volumes  was 
not  quite  correct.  To  him  the  particles  of  a  gaseous  ele- 
ment in  the  uncombined  state  were  isolated  atoms.  While 
he  distinguished  between  the  particles  of  compounds  and 
the  atoms  of  elements,  he  failed  to  distinguish  between  the 
free  particles  of  elements  and  their  atoms.  That  the  parti- 
cle of  an  element  might  be  made  up  of  two  or  more  single 
atoms,  it  would  have  been  impossible  for  him  to  admit ;  for, 
according  to  his  electro-chemical  theory  only  unlike  atoms 
could  exist  in  combination  with  one  another.  Avogadro's 
memoir  of  1811,  in  which  more  correct  views  on  the  subject 
had  been  advanced,  therefore  remained  unnoticed,  and  Ber- 
zelius '  atomic  weights  were  for  years  employed  by  all.  Nor 
were  most  of  those  figures  wrong;  for  in  many  cases  Ber- 

1  New  International  Encyclopaedia. 


228  MODERN  SCIENCE  READER 

zelius'  error  eliminated  itself,  owing  to  the  fact  that  the 
molecules  of  the  ordinary  gaseous  elements  are  made  up  of 
equal  numbers  of  atoms.  Knowing  the  true  atomic  weights 
of  the  ordinary  gaseous  elements,  Berzelius  was  able  to 
obtain  correct  figures  for  many  other  elements,  with  the  aid 
of  the  principle  of  isomorphism  and  certain  other  principles 
that  need  not  be  explained  here.  Thus,  his  figure  for  mer- 
cury was  200,  that  for  phosphorus  31,  that  for  sulphur  32 
—figures  practically  identical  with  those  accepted  at  pres- 
ent. In  1827,  however,  Dumas  invented  his  celebrated 
method  of  determining  vapor  densities,  and  undertook  to 
apply  Berzelius'  principle  of  equal  volumes  to  elements 
which  are  not  ordinarily  gaseous.  Finding  that  the  vapor 
of  mercury  is  101  times  as  heavy  as  an  equal  volume  of 
hydrogen,  the  vapor  of  phosphorus  62.8  times,  and  the 
vapor  of  sulphur  96  times,  as  heavy  as  hydrogen,  Dumas 
concluded  that  the  relative  weights  of  their  atoms  must  be, 
respectively,  101,  62.8  and  96,  and  not  200,  31  and  32  as 
Berzelius  thought.  The  error  of  Berzelius'  principle  thus 
emerged  in  the  results  of  Dumas.  But  instead  of  rectifying 
the  error  of  his  principle  by  introducing  the  concept  of  the 
molecules  of  elements,  Berzelius  only  concluded  that  the 
principle  was  unreliable.  The  result  was  that  chemists 
began  to  disagree  as  to  the  true  values  of  the  atomic  weights, 
and  many  even  abandoned  the  hope  of  ever  knowing  atomic 
weights  altogether,  and  decided  to  use  nothing  but  equiva- 
lents. These  represented  the  weights  of  elements  that  were 
capable  of  combining  with,  or  of  being  replaced  by,  unit 
weight  of  hydrogen.  For  example,  Berzelius'  view  that  an 
atom  of  oxygen  was  16  times  as  heavy  as  an  atom  of  hydro- 
gen was  abandoned,  and  as  hydrogen  combined  with  8  times 
its  weight  of  oxygen  the  latter  was  represented  by  its 
equivalent  8.  But  the  use  of  equivalents  was  not  universal, 
many  chemists  using  systems  in  which  the  figures  were 
partly  equivalents,  partly  atomic  weights,  and  thus  for 
years  great  confusion  reigned  in  chemical  notation,  the  true 
purpose  of  which  is  to  avoid  confusion  by  exhibiting  the 


CHEMISTRY  AND  ITS  DEVELOPMENT      229 

composition  of  substances  in  the  simplest  and  clearest  pos- 
sible manner.  In  the  forties  Laurent  and  Gerhardt  became 
convinced  that  the  progress  of  knowledge  in  organic  chem- 
istry was  seriously  impeded  by  the  lack  of  a  consistent 
system  of  atomic  weights.  Their  researches  soon  led  them 
to  distinguish  clearly  between  the  atoms  and  molecules  of 
elements,  and  to  grasp  the  full  value  of  Avogadro's  prin- 
ciple for  determining  the  relative  weights  of  molecules. 
With  the  aid  of  this  principle,  Gerhardt  found  the  true 
atomic  weights  of  the  elements;  and,  in  the  latter  part  of 
the  fifties,  his  pupil  Cannizzaro  demonstrated  clearly  the 
consistency  of  the  principle  with  all  known  facts.  Thus 
was  paved  the  way  for  the  doctrine  of  valency.  A  few 
years  later  (in  1869)  Mendeleeff  and  Lothar  Meyer  estab- 
lished a  remarkable  connection  between  the  properties  of 
the  elements  and  their  atomic  weights  (see  Periodic  Law)1 
and  thus  the  correctness  of  the  latter  was  confirmed  in  a 
very  striking  manner. 

The  further  progress  of  general  chemistry  has  been 
mainly  in  connection  with  the  various  subdivisions  of 
physical  chemistry,  brief  historical  accounts  of  which  may 
be  found  under  the  following  headings :  Reaction,  Solution, 
Dissociation,  Thermo-chemistry,  Electro-chemistry  and 
Laboratory.1 

*New  International  Encyclopaedia. 


THE  AGE  OF  SCIENCE1 

BY  IKA  KEMSEN,  PH.  D. 
President    of   the    Johns    Hopkins    University 

As  much  of  the  time  of  those  who  go  forth  from  this 
institution  to-day  has  been  spent  in  the  study  of  the 
sciences,  it  has  seemed  to  me  fitting  to  ask  your  attention 
to  some  considerations  suggested  by  the  phrase,  "This  is 
the  age  of  science".  I  do  not  remember  ever  to  have  heard 
this  statement  questioned,  much  less  denied,  nor  do  I  re- 
member ever  to  have  heard  it  satisfactorily  explained.  It 
sounds  simple  enough,  and  does  not  appear  to  call  for 
explanation  or  comment,  and  yet  I  think  it  worth  while  to 
examine  it  a  little  more  carefully  than  is  customary,  to  see 
in  what  sense  it  is  true.  For  in  a  sense  it  is  true,  and  in  a 
sense  it  is  not  true.  The  statement  raises  two  questions 
which  should  be  answered  at  the  outset.  These  are:  (1) 
What  is  science?  and  (2)  In  what  sense  is  this  the  age  of 
science  ? 

First,  then,  what  is  science?  Surely  there  can  be  no 
difficulty  in  answering  this,  and  yet  I  fear  that,  if  I  should 
pass  through  this  or  any  other  audience  with  the  question, 
I  should  get  many  different  answers. 

A  certain  lady,  whom  I  know  better  than  any  other,  has 
told  me  that,  should  she  ever  be  permitted  to  marry  a  sec- 
ond time,  she  would  not  marry  a  scientific  man,  because 
scientific  men  are  so  terribly  accurate.  I  often  hear  the 
same  general  idea  expressed,  and  it  is  clear  that  accuracy 
is  one  attribute  of  science  according  to  prevailing  opinions. 
But  accuracy  alone  is  not  science.  When  we  hear  a  game 
of  baseball  or  of  whist  spoken  of  as  thoroughly  scientific,  I 

Commencement  address  delivered  at  Worcester  Polytechnic  Insti- 
tute, June  9,  1904.  Published  in  Science  for  July  15,  1904. 

230 


THE  AGE  OF  SCIENCE  231 

suppose  the  idea  here,  too,  is  that  the  games  are  played 
accurately;  that  is,  to  use  the  technical  expression,  without 
errors. 

Again,  there  are  those  who  seem  to  think  that  science  is 
something  that  has  been  devised  by  the  Evil  One  for  the 
purpose  of  undermining  religion.  This  idea  is  not  so  com- 
mon as  it  was  a  few  years  ago,  when  the  professors  of 
scientific  subjects  in  our  colleges  were  generally  objects  of 
suspicion.  The  change  which  has  come  over  the  world  in 
this  respect  within  my  own  memory  is  simply  astounding. 
In  general  terms  an  agreement  has  been  reached  between 
those  who  represent  religion  and  those  who  represent 
science.  This  agreement  is  certainly  not  final,  but  it  gives 
us  a  modus  Vivendi,  and  the  clash  of  arms  is  now  rarely 
heard.  Religion  now  takes  into  consideration  the  claims 
of  science,  and  science  recognizes  the  great  fundamental 
truths  of  religion.  Each  should  strengthen  the  other,  and 
in  time,  no  doubt,  each  will  strengthen  the  other. 

Probably  the  idea  most  commonly  held  in  regard  to 
science  is  that  it  is  something  that  gives  us  a  great  many 
useful  inventions.  The  steam-engine,  the  telegraph,  the 
telephone,  the  trolley  car,  dyestuffs,  medicines,  explosives 
—these  are  the  fruits  of  science,  and  without  these  science 
is  of  no  avail.  I  propose  farther  on  to  discuss  this  subject 
more  fully  than  I  can  at  this  stage  of  my  remarks,  so  that 
I  may  pass  over  it  lightly  here.  I  need  only  say  now  that 
useful  inventions  are  not  a  necessary  consequence  of  scien- 
tific work,  and  that  scientific  work  does  not  depend  upon 
useful  applications  for  its  value.  These  propositions, 
which  are  familiar  enough  to  scientific  men,  are  apt  to 
surprise  those  who  are  outside  of  scientific  circles.  I  hope 
before  I  get  through  to  show  you  that  the  propositions  are 
true. 

Science,  then,  is  not  simply  accuracy,  although  it  would 
be  worthless  if  it  were  not  accurate;  it  is  not  devised  for 
the  purpose  of  undermining  religion;  and  its  object  is  not 
the  making  of  useful  inventions.  Then  what  is  it?  One 


232  MODERN  SCIENCE  READER 

dictionary  gives  this  definition :  * '  Knowledge ;  knowledge 
of  principles  and  causes;  ascertained  truth,  or  facts.  .  .  . 
Accumulated  and  established  knowledge  which  has  been 
systematized  and  formulated  with  reference  to  the  dis- 
covery of  general  truths  or  the  operation  of  general  laws, 
.  .  .  especially  such  knowledge  when  it  relates  to  the 
physical  world,  and  its  phenomena,  the  nature,  constitution 
and  forces  of  matter,  the  qualities  and  function  of  living 
tissues,  etc." 

One  writer  says:  "The  distinction  between  science  and 
art  is  that  science  is  a  body  of  principles  and  deductions  to 
explain  the  nature  of  some  matter.  An  art  is  a  body  of 
precepts  with  practical  skill  for  the  completion  of  some 
work.  A  science  teaches  us  to  know;  an  art,  to  do.  In 
art,  truth  is  a  means  to  an  end ;  in  science  it  is  the  only  end. 
Hence  the  practical  arts  are  not  to  be  classed  among  the 
sciences."  Another  writer  says:  "Science  and  art  may 
be  said  to  be  investigations  of  truth;  but  one,  science,  in- 
quires for  the  sake  of  knowledge ;  the  other,  art,  for  the 
sake  of  production;  and  hence  science  is  more  concerned 
with  the  higher  truths,  art  with  the  lower;  and  science 
never  is  engaged,  as  art  is,  in  productive  application." 

Science,  then  has  for  its  object  the  accumulation  and 
systematization  of  knowledge,  the  discovery  of  truth.  The 
astronomer  is  trying  to  learn  more  and  more  about  the 
celestial  bodies,  their  motions,  their  composition,  their 
changes.  Through  his  labors,  carried  on  for  many  cen- 
turies, we  have  the  science  of  astronomy. 

The  geologist  has,  on  the  other  hand,  confined  his  atten- 
tion to  the  earth,  and  he  is  trying  to  learn  as  much  as  pos- 
sible of  its  composition  and  structure,  and  of  the  processes 
that  have  been  operating  through  untold  ages  to  give  us 
the  earth  as  it  now  is.  He  has  given  us  the  science  of 
geology,  which  consists  of  a  vast  mass  of  knowledge  care- 
fully systematized  and  of  innumerable  deductions  of  in- 
terest and  value.  If  the  time  should  ever  come  when, 
through  the  labors  of  the  geologist,  all  that  can  possibly  be 


THE  AGE  OF  SCIENCE  233 

learned  in  regard  to  the  structure  and  development  of  the 
earth  shall  have  been  learned,  the  occupation  of  the  geolo- 
gist would  be  gone.  But  that  time  will  never  come. 

And  so  I  might  go  on  pointing  out  the  general  character 
of  the  work  done  by  different  classes  of  scientific  men,  but 
this  would  be  tedious.  We  should  only  have  brought  home 
to  us  in  each  case  the  fact  that,  no  matter  what  the  science 
may  be  with  which  we  are  dealing,  its  disciples  are  simply 
trying  to  learn  all  they  can  in  the  field  in  which  they  are 
working.  As  I  began  with  a  reference  to  astronomy,  let 
me  close  with  a  reference  to  chemistry.  Astronomy  has 
to  deal  with  the  largest  bodies,  and  the  greatest  distances 
of  the  universe;  chemistry,  on  the  other  hand,  has  to  deal 
with  the  smallest  particles  and  the  shortest  distances  of 
the  universe.  Astronomy  is  the  science  of  the  infinitely 
great ;  chemistry  is  the  science  of  the  infinitely  little.  The 
chemist  wants  to  know  what  things  are  made  of,  and,  in 
order  to  find  this  out,  he  has  to  push  his  work  to  the  small- 
est particles  of  matter.  Then  he  comes  face  to  face  with 
facts  that  lead  him  to  the  belief  that  the  smallest  particles 
he  can  weigh  by  the  aid  of  the  most  delicate  balance,  and 
the  smallest  particles  he  can  see  by  the  aid  of  the  most 
powerful  microscope,  are  immense  as  compared  with  those 
of  which  he  has  good  reason  to  believe  the  various  kinds  of 
matter  to  be  made  up.  It  is  for  this  reason  that  I  say  that 
chemistry  is  the  science  of  the  infinitely  little. 

Thus  have  I  tried  to  show  what  science  is  and  what  it  is 
not.  Now  let  me  turn  to  the  second  question. 

In  what  sense  is  this  the  age  of  science?  In  the  first 
place,  it  is  not  true  that  science  is  something  of  recent 
birth.  Scientific  work  of  one  kind  and  another  has  been 
in  progress  for  ages — not  in  all  branches,  to  be  sure — but 
nature  has  always  engaged  the  attention  of  man,  and  we 
may  be  sure  that  he  has  always  been  trying  to  learn  more 
about  it.  The  science  of  astronomy  was  the  first  to  be 
developed.  Astrology  was  its  forerunner.  Then  came 
chemistry  in  the  guise  of  alchemy.  It  would  be  interest- 


234  MODERN  SCIENCE  READER 

ing  to  follow  the  development  of  each,  and  to  see  how 
from  the  crude  observations  and  imaginings  of  the  earlier 
generations  came  the  clearer  and  broader  conceptions  that 
constitute  the  sciences,  but  time  will  not  permit  us  to  enter 
upon  this  subject.  I  cannot,  however,  do  justice  to  my 
theme  without  calling  your  attention  to  one  of  the  most 
serious  obstacles  that  stood  in  the  way  of  the  advance  of 
knowledge. 

To  make  clear  the  nature  of  this  obstacle,  it  will  be  best 
to  make  a  comparison.  A  child  learns  a  great  deal  in  regard 
to  his  surroundings  in  his  earliest  years  before  he  goes  to 
school,  and  without  the  aid  of  his  parents.  He  is  con- 
stantly engaged  in  making  observations  and  drawing  con- 
clusions, and  his  actions  are  largely  guided  by  the  knowledge 
thus  gained.  After  a  time  school  life  begins,  and  the 
child  then  begins  to  study  books  and  to  acquire  knowledge 
at  second-hand.  This  is  an  entirely  different  process  from 
that  by  which  he  gained  his  first  knowledge.  The  latter  is 
natural,  the  former  is  artificial.  Then,  too,  he  soon  dis- 
covers that  many  things  he  sees  call  for  explanation,  and 
he  is  led  to  wonder  what  the  explanation  is.  If  he  has  a 
strong  imagination,  as  most  children  have,  he  will  probably 
think  out  some  explanation.  He  finds  that  he  can  use  his 
mind,  and  that  this  helps  him  in  dealing  with  the  facts  in 
nature.  Now  comes  the  danger.  It  being  much  easier  to 
think  than  to  work,  the  chances  are  that  in  trying  to  find 
the  explanation  of  things,  he  will  give  up  the  natural 
method  and  be  satisfied  with  the  products  of  his  imagina- 
tion. He  will  gradually  give  up  dealing  directly  with 
things,  and  take  to  thinking  alone.  When  this  stage  is 
reached  his  knowledge  will  increase  very  slowly,  if  at  all. 

Whether  this  picture  of  the  development  of  a  child  is  in 
accordance  with  the  facts  of  life  or  not,  it  gives  an  idea  of 
the  mental  development  of  mankind.  First  came  the 
period  of  infancy,  during  which  observations  were  made 
and  much  learned.  Efforts  were  early  made  to  explain 
the  facts  of  nature.  We  have  remnants  of  these  explana- 


THE  AGE  OF  SCIENCE  235 

tions  in  old  theories  that  have  long  ceased  to  be  useful. 
They  no  doubt  served  a  useful  purpose  in  their  day,  but 
gradually  one  of  the  most  pernicious  ideas  ever  held  by 
man  took  shape,  and  I  am  willing  to  characterize  it  as  one 
of  the  most  serious  obstacles  to  the  advance  of  knowledge. 
I  refer  to  the  idea  that  it  is  a  sign  of  inferiority  to  work 
with  the  hands.  This  idea  came  early  and  stayed  late. 
In  fact,  there  are  still  on  the  earth  a  few  who  hold  it. 
How  did  this  prove  an  obstacle  to  the  advance  of  knowl- 
edge? By  preventing  those  who  were  best  equipped  from 
advancing  knowledge.  The  learned  men  of  the  earth  for 
a  long  period  were  thinkers,  philosophers.  They  were  not 
workers  in  nature's  workshop.  They  tried  to  solve  the  great 
problems  of  nature  by  thinking  about  them.  They  did 
not  experiment.  That  is  to  say,  they  did  not  go  directly 
to  nature  and  put  questions  to  her.  They  speculated. 
They  elaborated  theories.  During  this  period  knowledge 
was  not  advanced  rapidly.  It  could  not  be.  For  the  only 
way  along  which  advances  could  be  made  was  closed. 

Slowly  the  lesson  was  learned  that  the  only  way  by  which 
we  can  gain  knowledge  of  nature's  secrets  is  by  taking  her 
into  our  confidence.  Instead  of  contemplating  in  a  study, 
we  must  have  contact  with  the  things  of  nature  either  out- 
of-doors  or  in  the  laboratory.  Manual  labor  is  necessary. 
Without  it  we  may  as  well  give  up  hope  of  acquiring  knowl- 
edge of  the  truth.  When  this  important  fact  was  forced 
upon  the  attention  of  men,  scientific  progress  began  and 
continued  with  increasing  rapidity.  At  present  the  old 
pernicious  idea  that  a  man  who  does  any  kind  of  work 
with  his  hands  is  by  virtue  of  that  fact  an  inferior  being— 
that  idea  is  no  longer  generally  held.  But  we  have  not 
got  entirely  rid  of  it.  In  a  recent  address  I  find  this  refer- 
ence to  the  subject:  "However  the  case  may  have  been 
with  what  forty  years  ago  was  called  the  education  of  a 
gentleman,  it  seems  to  me  to  be  one  of  the  services  of  the 
scientific  laboratory  that  it  has  taught  to  that  part  of  man- 
kind which  has  leisure  and  opportunities  that  manual  skill 


236  MODERN  SCIENCE  READER 

is  a  thing  to  be  held  in  honor  both  as  a  means  for  reaching 
mechanical  results,  and  still  more,  as  a  way  to  train  the 
mind.  .  .  .  Fifty  years  ago  many  men  who  called  them- 
selves educated  were  mere  untrained,  undeveloped  children 
in  manual  skill,  and  some  of  them  were  proud  of  their 
incompetency,  for  nothing  would  have  more  surprised 
them  than  an  assertion  that  their  inability  to  help  them- 
selves with  their  hands  was  a  badge  of  ignorance.  .  .  . 
While  the  high  character  and  sterling  worth  of  the  medical 
man  has  always  won  respect,  their  skill  in  the  use  of  their 
hands  was  long  held  by  those  who  were  superior  to  such 
weakness  to  place  them  beneath  the  lawyers  and  the  clergy- 
men in  the  social  scale.'/  Recently  I  came  upon  this  old 
idea  within  college  walls.  In  the  college  connected  with 
the  Johns  Hopkins  University  there  are  several  groups  of 
studies  which  lead  to  the  degree  of  bachelor  of  arts. 
Group  I  is  largely, made  up  of  the  classics,  and  it  is  there- 
fore generally  called  the  classical  group.  I  happened 
once  to  be  dining  with  a  gentleman  whose  son  was  a  stu- 
dent in  Group  I  in  our  college.  Our  professor  of  Latin 
was  also  present.  Turning  to  my  colleague,  the  professor 
of  Latin,  our  host,  the  father  of  the  classical  student,  ex- 
claimed: "How  those  fellows  in  Group  I  look  down  upon 
all  the  others!"  I  afterward  learned  that  this  feeling 
undoubtedly  existed  among  the  students,  those  who  studied 
the  classics,  especially,  forming,  in  their  own  opinion  at 
least,  a  well-characterized  aristocracy.  I  have  referred  to 
these  cases  simply  for  the  purpose  of  showing  that  the 
pernicious  idea  that  hand-work  is  a  sign  of  inferiority  is 
not  yet  dead.  But  it  has  nevertheless  been  disappearing 
rapidly  for  some  years  past,  and  with  its  disappearance 
the  development  of  science  has  kept  pace.  Which  is  the 
cause  and  which  the  effect  it  would  perhaps  be  hard  to  say. 
At  all  events,  the  growth  of  every  department  of  science 
has  been  more  rapid  within  the  last  fifty  years  than  during 
the  preceding  fifty  years,  though  we  should  be  doing  gross 
injustice  to  our  predecessors  were  we  to  belittle  their  work. 


THE  AGE  OF  SCIENCE  237 

The  fact  is,  I  am  inclined  to  think  that  there  never  was  a 
more  fruitful  period,  in  chemistry  at  least,  than  the  last 
quarter  of  the  eighteenth  century.  Farther  on,  I  shall 
have  occasion  to  speak  of  a  few  of  the  great  chemical  dis- 
coveries that  were  made  during  that  period.  No  greater 
discoveries  have  been  made  since.  In  astronomy,  Newton's 
great  work  was  done  more  than  two  centuries  ago.  An 
age  that  can  boast  of  the  discovery  of  the  law  of  gravitation 
may  fairly  lay  claim  to  the  title,  "the  age  of  science." 
Many  and  many  a  great  discovery  in  science  preceded  the 
present  age,  but  from  what  I  have  already  said,  you  will 
see  that  the  reason  for  calling  this  age  in  which  we  live  the 
scientific  age  is  found  in  the  fact  that  scientific  work  is 
much  more  extensively  carried  on  at  present  than  at  any 
time  in  the  past,  and,  further,  the  world  is  beginning  to 
reap  the  rewards  of  this  work.  So  striking  are  some  of 
these  rewards  that  they  appeal  to  all.  The  world  is  daz- 
zled by  them,  and  is  to  a  large  extent  unable  to  distinguish 
between  the  scientific  work  which  has  made  these  rewards 
possible  and  the  rewards  themselves.  The  idea  is  preva- 
lent that  scientific  work  is  carried  on  in  order  that  rewards 
in  the  shape  of  practical  results  may  be  reached.  I  have 
no  desire  to  bring  my  fellow-workers  in  science  into  disre- 
pute. It  would  therefore  perhaps  be  best  for  me  to  stop 
here;  but,  if  you  will  bear  with  me,  I  will  try  to  make  it 
clear  to  you  that  one  may  be  engaged  in  scientific  work  all 
his  life,  never  thinking  of  what  the  world  calls  practical 
results,  that  he  may  in  fact  not  achieve  a  single  result  that 
can  be  called  practical,  and  yet  not  waste  his  time ;  and 
that  one  may  hold  such  a  worker  up  to  admiration  without 
running  much  risk  of  being  taken  for  a  fool.  This  will  be 
my  object  in  what  I  still  have  to  say. 

While  I  have  thus  far  referred  to  science  in  the  broadest 
sense,  meaning  the  science  of  nature,  let  me  now  turn  more 
especially  to  the  science  to  which  it  has  been  my  lot  to 
devote  my  life,  and  let  me  endeavor  to  show  by  a  few 
examples  the  relations  that  exist  between  work  that  appears 


238  MODERN  SCIENCE  READER 

to  be  of  little  practical  value  when  first  performed  and 
results  that,  from  the  industrial  point  of  view,  are  of  the 
highest  value. 

I  have  often  been  embarrassed  by  these  questions  put 
to  me  in  my  laboratory:  ''What  are  you  doing?"  and  "Of 
what  use  is  the  work?"  Generally  I  am  obliged  to  answer 
to  the  first,  "I  regret  that  I  cannot  possibly  explain  what 
I  am  doing.  I  have  tried  to  do  so  in  some  cases,  but  I 
have  been  begged  to  stop";  and  to  the  second,  the  only 
possible  answer  has  been,  "I  do  not  know."  I  am  well 
aware  that  such  answers  seem  to  show  that  the  work  is  in 
fact  of  no  value,  and  that  this  is  the  impression  that  my 
visitors  carry  away  with  them.  Now  I  do  not  propose  to 
try  to  justify  my  own  work,  nor  to  try  to  explain  it.  For 
the  most  part  it  has  had  to  deal  with  matters  that  do  not 
touch  our  daily  lives,  and  therefore  it  cannot  be  made  inter- 
esting, not  to  say  intelligible.  I  shall,  to  be  sure,  show  you 
how  one  piece  of  work  carried  out  twenty  years  ago  has 
become  of  world-wide  interest,  though  when  it  was  carried 
out  it  appeared  as  little  likely  to  be  of  practical  value  as 
anything  ever  done.  But  this  is  anticipating. 

During  the  latter  half  of  the  eighteenth  century  there 
lived  in  Sweden  a  poor  apothecary  who,  in  his  short  life, 
probably  did  more  to  enlarge  our  knowledge  of  chemistry 
than  any  other  man.  Throughout  his  life  he  had  to  contend 
with  sickness  and  poverty.  He  was  obliged  to  carry  on  the 
business  of  an  apothecary  in  order  to  keep  the  wolf  from 
entering  his  house— he  never  succeeded  in  keeping  it  from 
the  door.  His  great  delight  was  to  investigate  things 
chemically,  and  to  find  out  all  he  could  about  them.  It  is 
simply  astounding  to  the  chemist  to  find  how  many  dis- 
coveries of  the  highest  importance  he  made.  But  I  have 
not  mentioned  his  name.  I  refer  to  the  immortal  Scheele. 
He  died  in  the  year  1786  at  the  age  of  43,  yet  he  will  al- 
ways be  remembered,  and  those  who  know  most  of  the 
work  he  did  will  respect  him  most. 

Though  Scheele  was  an  apothecary,  his  chemical  work 


THE  AGE  OF  SCIENCE  239 

was  not  practical  in  the  ordinary  sense,  and  it  was  no 
doubt  often  difficult  for  him  to  explain  what  he  was  doing. 
His  most  important  discovery  was  that  of  oxygen— a  dis- 
covery that  was  made  at  the  same  time  (1774)  by  the 
English  clergyman,  Priestley.  Chemists  know  that  this  is 
one  of  the  most  important  discoveries  ever  made  in  the 
field  of  chemistry,  and,  filled  with  this  conviction,  in  1874, 
one  hundred  years  after  the  discovery  was  made,  the  chem- 
ists of  the  United  States  made  a  pilgrimage  to  Northumber- 
land on  the  Susquehanna  to  do  honor  to  the  memory  of 
Priestley,  who  there  spent  the  last  years  of  his  life. 

But  why  was  this  discovery  so  important?  Oxygen,  to 
be  sure,  is  the  most  widely  distributed  and  the  most  abund- 
ant substance  in  and  on  the  earth;  it  plays  a  controlling 
part  in  the  breathing  of  animals,  and  in  most  of  the 
changes  that  are  taking  place  upon  the  earth ;  a  knowledge 
of  it  and  of  the  ways  in  which  it  acts  has  done  more  than 
anything  else  to  give  chemists  an  insight  into  chemical 
action  in  general ;  and  therefore  has  contributed  more  than 
anything  else  to  the  development  of  chemistry.  All  this  is 
no  doubt  true,  but  are  these  results  practical?  Could  we 
go  out  into  the  world  and  form  a  company  and  sell  stock 
on  the  basis  of  such  a  discovery?  Or  could  the  discoverer 
in  any  way  realize  in  cash  ?  The  average  man  of  the  world 
would  say:  "No!  there  is  nothing  in  it.  It  may  be  well 
for  a  few  men  who  have  not  the  power  to  compete  with 
their  fellow-men  in  the  busy  marts  to  devote  themselves  to 
such  useless  pursuits.  Possibly  something  may  come  of  it 
in  time,  but  better  something  practical,  something  that 
can  be  converted  into  hard  cash.  That  is  the  test,  and  the 
only  fair  test  by  which  we  can  judge  whether  any  partic- 
ular piece  of  scientific  work  is  or  is  not  of  value." 

But  I  have  already  said  that  the  discovery  of  oxygen 
was  the  most  important  discovery  ever  made  in  chemistry, 
and  I  might  have  added,  the  most  valuable.  In  what,  then, 
did  its  value  consist?  In  the  fact  that  it  led  to  a  more 
intelligent  working  with  all  things  chemical.  Operations 


240  MODERN  SCIENCE  READER 

that  had  betore  this  discovery  appeared  mysterious  sud- 
denly became  clear,  and  every  one  engaged  in  chemical 
work  was  helped  in  many  ways.  If  it  is  not  enough  for 
us  simply  to  gain  a  clearer  insight  into  the  processes  around 
us,  if  we  must  insist  upon  more  tangible  reward,  no  doubt 
it  could  be  shown  that  the  discovery  of  oxygen  has  con- 
tributed largely  to  the  material  welfare  of  mankind— not 
directly  perhaps,  but  by  enlarging  our  knowledge  of  chem- 
istry, so  that  it  may  be  said  that  most  discoveries  made 
since  1774  have  been  in  a  way  consequences  .of  the  dis- 
covery of  oxygen.  Indirect  results  are  often  of  more  value 
than  direct  ones. 

But  there  is  another  discovery  of  Scheele's  that  illus- 
trates in  another  way  that  a  discovery  which  when  made 
appears  of  little  or  no  practical  value,  may  eventually 
prove  of  immense  practical  value  and  become  the  basis  of 
a  great  industry.  This  is  the  discovery  of  chlorine. 
Among  the  many  substances  examined  by  Scheele  was  one 
that  is  commonly  known  as  black  oxide  of  manganese.  This 
occurs  in  nature  in  large  quantity  and  has  long  been  of 
interest  to  chemists.  Scheele  treated  this  with  about  every- 
thing he  could  lay  his  hands  on,  as  was  his  way.  When 
muriatic  acid,  or,  as  it  was  called  by  the  older  chemists, 
the  spirit  of  salt,  was  poured  on  the  black  oxide  of  manga- 
nese, he  noticed  that  something  unusual  took  place.  He 
soon  became  aware  that  a  colored  gas  was  given  off,  and  that 
this  gas  had  other  properties  besides  that  of  color.  It 
affected  his  eyes,  nose,  throat  and  lungs  in  most  disagree- 
able ways.  Many  of  those  before  me  have  had  the  exper- 
ience of  inhaling  a  little  of  this  gas.  I  hope  no  one  has 
inhaled  much  of  it.  It  is  one  of  the  most  disagreeable 
things  chemists  and  students  of  chemistry  have  to  deal 
with.  And  it  is  not  only  disagreeable,  it  is  extremely 
poisonous.  But  Scheele  did  not  stop  his  work  because  it 
involved  discomfort  and  even  danger.  He  persisted  and 
carried  it  to  a  successful  issue,  and  when  he  stopped  he 
was  able  to  give  as  satisfactory  an  account  of  the  now 


THE  AGE  OF  SCIENCE  241 

familiar  chlorine  as  we  can  give  to-day.  The  investigation 
is  a  model.  It  could  not  have  been  accomplished  without 
the  enthusiasm,  the  patience,  the  knowledge  and  the  skill 
possessed  by  Scheele.  No  ordinary  chemist  would  have 
been  equal  to  it.  We  shall  not  overstate  the  case  if  we  say 
that  Scheele 's  discovery  of  chlorine  ranks  with  the  most 
important  and  the  most  valuable  of  chemical  discoveries. 
That  of  oxygen  outranks  it  certainly,  but  chlorine  falls  in 
line  not  far  behind. 

Now,  why  was  this  an  important  and  a  valuable  dis- 
covery? Primarily  because  it,  like  the  discovery  of 
oxygen,  though  to  a  less  degree,  aided  chemists  in  their 
efforts  to  understand  chemistry  and  thus  to  put  them  in  a 
position  to  deal  more  intelligently  with  chemical  problems 
of  all  kinds.  That  statement  may,  once  for  all,  be  made 
of  every  important  chemical  discovery.  But  while  Scheele 
had  no  thought  of  any  practical  uses  to  which  chlorine 
could  be  put,  and  his  discovery  was  not  at  first  regarded 
as  one  with  a  practical  bearing,  it  proved  eventually  to  be 
of  the  highest  practical  value,  and  to-day  it  plays  an 
exceedingly  important  part  in  practical  affairs.  As  is 
well  known,  chlorine  is  the  great  bleacher,  and  as  such  is 
used  in  enormous  quantity,  especially  for  bleaching  straw, 
paper  and  different  kinds  of  cloth.  As  it  would  be  ex- 
pensive and  inconvenient  to  transport  a  gas,  and  especially 
such  a  gas  as  chlorine,  it  is  locked  up,  as  it  were,  by  causing 
it  to  act  upon  lime,  and  the  " chloride  of  lime"  or  "bleach- 
ing powder"  thus  formed,  which  readily  gives  up  its 
chlorine,  is  a  most  important  article  of  commerce,  many 
thousands  of  tons  being  manufactured  annually.  Then 
again  chlorine  is  one  of  the  most  efficient  disinfectants, 
and  as  such  it  is  finding  more  and  more  extensive  use  every 
year,  and  is  plainly  contributing  to  the  welfare  of  man  by 
interfering  with  the  spread  of  disease.  Further,  it  is 
essential  to  the  manufacture  of  chloroform,  and  that  this 
calls  for  a  large  quantity  of  chlorine  will  appear  when  it 
is  stated  that  nearly  nine  tenths  of  the  weight  of  chloro^ 
16 


242  MODERN  SCIENCE  READER 

form  is  chlorine.  Chloroform,  which  has  been  of  such 
inestimable  value  as  an  alleviator  of  pain,  cannot  be  manu- 
factured without  chlorine,  and  it  could  never  have  been 
discovered  without  the  previous  discovery  of  chlorine. 

Finally,  without  attempting  to  give  a  full  account  of  all 
the  uses  to  which  chlorine  has  been  and  is  put  for  our 
benefit,  let  me  mention  one  more  application,  though  in 
doing  so  I  may  run  the  risk  of  leading  some  of  you  to  the 
conclusion  that  chlorine  has  its  dark  side  as  well  as  its 
light.  It  is  with  some  misgivings  that  I  venture  to  tell 
you  that  chlorine  has  found  extensive  application  in  the 
extraction  of  gold  from  its  ores,  and  as  gold  is  held  by  some 
to  be  the  root  of  all  evil,  chlorine  must,  by  the  same  token, 
be  regarded  as  particeps  criminis.  A  few  years  ago  I 
visited  the  gold  mines  in  the  Black  Hills  of  South  Dakota, 
and  there  I  spent  some  time  in  examining  the  chlorination 
process.  I  could  not  help  thinking  of  Scheele  and  his 
simple  experiments  that  first  brought  chlorine  to  light. 
I  wondered  whether,  if  he  could  see  the  extensive  applica- 
tions of  that  greenish-yellow  gas  that  first  set  him  to  weep- 
ing and  coughing— I  wondered  whether  his  satisfaction  in 
his  work  would  be  any  greater  than  it  must  have  been  when 
the  discovery  was  made.  Compare  the  little  room  in  the 
apothecary  shop,  the  simple  apparatus,  and  the  apparent 
uselessness  of  the  noxious  gas  with  the  great  factories,  the 
complicated  machinery  and  the  valuable  applications  al- 
ready mentioned,  and  it  is  evident  that  a  discovery  that 
appears  least  promising  from  the  practical  point  of  view 
may  be  the  beginning  of  the  most  valuable  industries. 

Before  leaving  this  part  of  my  subject  let  me  take  a 
much  less  important  example  than  those  already  spoken  of, 
but  one  that  comes  nearer  home.  Nearly  twenty-five  years 
ago  in  the  laboratory  under  my  charge,  an  investigation 
was  being  carried  on  that  seemed  as  little  likely  to  lead  to 
practical  results  as  any  that  could  well  be  imagined.  It 
would  be  quite  out  of  the  question  to  explain  what  we  were 
trying  to  do.  Any  practical  man  would  unhesitatingly 


THE  AGE  OF  SCIENCE  243 

have  condemned  the  work  as  being  utterly  useless,  and  I 
may  add  that  some  did  condemn  it.  There  was  no  hope, 
no  thought  entertained  by  us  that  anything  practical  would 
come  of  it.  But  lo!  one  day  it  appeared  that  one  of  the 
substances  discovered  in  the  course  of  the  investigation  is 
the  sweetest  thing  on  earth ;  and  then  it  was  shown  that  it 
can  be  taken  into  the  system  without  injury;  and  finally, 
that  it  can  be  manufactured  at  such  a  price  as  to  furnish 
sweetness  at  a  cheaper  rate  than  it  is  furnished  by  the 
sugar  cane  or  the  beet.  And  soon  a  great  demand  for  it 
was  created,  and  to-day  it  is  manufactured  in  surprising 
quantities  and  used  extensively  in  all  corners  of  the  globe. 
Thousands  have  found  employment  in  the  factories  in  which 
it  is  now  made,  and  it  appears  that  in  some  European 
countries  the  new  substance  has  become  the  sweetening 
agent  of  the  poor,  it  being  sold  in  solution  by  the  drop. 

It  is  unnecessary  here  to  discuss  the  question  naturally 
suggested  by  the  facts  just  spoken  of,  whether  the  discovery 
of  the  sweet  substance  has  benefited  the  human  race.  It 
would  be  extremely  difficult,  if  not  impossible,  to  answer  this 
question.  But  whatever  the  answer,  it  is  clear,  from  what 
has  been  said  that  the  discovery  was  of  importance  from  the 
practical  point  of  view,  and  there  was  nothing  originally  in 
the  work  to  suggest  the  possibility  of  a  practical  result  in  the 
sense  in  which  the  word  practical  is  commonly  employed. 

This  is  the  lesson  that  we  learn  over  and  over  again  as 
we  study  the  great  industries.  Rarely  have  they  been  the 
results  of  work  undertaken  with  the  object  of  attaining 
the  practical.  Look  at  the  beginnings  of  electricity.  A 
piece  of  amber  when  rubbed  attracts  bits  of  pith.  A  frog's 
leg  twitches  after  death  when  touched  in  certain  ways  with 
metals.  That  was  all.  Are  such  things  worth  investigat- 
ing? No  doubt  the  practical  man  said:  "No;  stop  trifling: 
do  something  worth  doing."  And  if  he  had  been  per- 
mitted to  have  his  way,  all  the  wonderful  results  that 
depend  upon  the  applications  of  electricity  would  have 
been  impossible.  In  every  line,  much  study,  much  work, 


244  MODERN  SCIENCE  READER 

and  much  investigation  are  absolutely  necessary  before 
enough  knowledge  can  be  got  together  to  make  profitable, 
practical  applications  possible.  During  this  early  pre- 
paratory stage  the  work  is  of  no  direct  interest  to  the 
purely  practical  man ;  and  yet  without  this  work  the 
applications  which  he  values  would  be  impossible.  Scien- 
tific work  in  its  highest  form  does  not  pay  directly.  Those 
who  devote  themselves  to  the  pursuit  of  pure  science  do  not, 
as  a  rule,  reap  pecuniary  reward.  They  probably  enjoy 
their  lives  as  much  as  if  they  did,  though  it  is  often  difficult 
to  make  them  believe  this.  But  because  it  does  not  yield 
immediate  reward  to  the  worker,  should  the  work  stop? 
Surely  not.  Our  only  hope  of  progress  in  intellectual  as 
well  as  practical  matters  lies  in  a  continuation  of  this  work. 
And  even  though  not  a  single  tangible,  practical  result 
should  be  reached,  the  work  would  be  valuable.  Why? 
Because  we  are  all  helped  by  knowledge.  The  more  we 
know  of  the  universe  the  better  fitted  we  are  to  fill  our 
places  in  the  world.  All  will  concede  the  truth  of  that 
proposition.  But  if  this  is  true  we  have  the  strongest 
argument  for  scientific  work,  for  it  is  only  through  such 
work  that  we  are  enlarging  our  knowledge.  There  is  no 
other  way  of  learning.  Somebody  must  be  adding  to  our 
stock  of  knowledge,  or  what  we  call  progress  in  intellectual 
and  material  things  would  stop.  It  also  seems  probable 
that  moral  progress  is  aided  by  intellectual  progress,  though 
it  might  be  difficult  to  make  this  perfectly  clear.  I  believe 
it  is  so;  though  of  course  it  does  not  follow  that  every 
individual  furnishes  evidence  of  the  relation  between  intel- 
lectual and  moral  progress. 

But,  my  friends,  whether  we  will  or  not,  scientific  inves- 
tigation will  go  on  as  it  has  been  going  on  from  the  earliest 
times,  and  it  will  go  on  more  and  more  rapidly  with  time. 
The  universe  is  inexhaustible,  and  its  mysteries  are  inex- 
plicable. We  may  and  must  strive  to  learn  all  we  can,  but 
we  cannot  hope  to  learn  all.  We  are  finite;  the  mysteries 
we  are  dealing  with  are  infinite. 


THE  OLD  AND  THE  NEW  ALCHEMY1 

1.  Les    Origines    de    I'Alchimie.     Par    M.    BERTHELOT.     Paris: 
Georges  Steinheil.     1885. 

2.  Die  Alchemie  in  alter er  und  neuerer  Zeit.     Von  HERMANN  KOPP. 
Heidelberg:   Carl  Winter.     1886. 

3.  Histoire   de   la  Philosophic  Hermetique.     Par    N.   LENGLET   DU 
FRESNOY.     3  vols.    Paris.     1742. 

4.  Das  Letzte  AufflacJcern  der  Alchemie  in  Deutschland.     Von  E. 
SCHULTZE.    Leipzig.     1897. 

5.  Lives    of    Alchemistical    Philosophers.     By    ARTHUR    EDWARD 
WAITE.     London.     1888. 

6.  'Radio- Active     Transformations.     By     E.     RUTHERFORD,     F.R.S. 
London:   A.  Constable.     1906. 

TIME  does  indeed  " bring  in  his  revenges."  Old  Horace 
knew  it,  and  we  are  experiencing  the  truth  of  his  Multa 
renascentur.  Thought,  like  the  planets,  has  its  'stations 
and  retrogradations. '  Now  and  again,  its  course  seems 
not  unfitly  symbolized  by  the  mystic  ouroboros,  or  coiled 
serpent.  The  head  has  overtaken  the  tail.  Yet  we  do  not 
really  get  back  to  the  starting-point.  There  are  no  closed 
circuits  in  human  affairs.  The  very  earth  progresses 
spirally.  It  wheels  round  a  sun  on  the  march,  and  returns 
no  more  on  last  year's  track. 

Modern  physicists  have  not  then  reverted  to  the  precise 
theories  of  Stephanus  of  Alexandria,  still  less  to  the  prac- 
tices, however  legitimate  in  their  time,  of  Friar  Bacon  or 
Cornelius  Agrippa.  But  they  have  gained  a  point  of  view 
from  which  the  search  for  the  philosopher's  stone  appears 
less  aberrant  from  reason  than  it  did  to  their  confident 
predecessors  in  the  Victorian  era.  The  attitude  of  science 
has  been  notably  changed  by  the  disclosure  of  electronic 
activities.  Possibilities  are  now  taken  into  serious  account 

Published  in  The  Edinburgh  Eeview  for  January,  1907. 
245 


246  MODERN  SCIENCE  READER 

which,  a  very  few  years  ago,  were  either  ignored  or  derided. 
Especially  as  regards  the  constitution  of  matter,  ideas  have 
come  to  be  prevalent  which  may  literally  be  termed  "revo- 
lutionary," since  they  curve  backward  irresistibly  toward 
those  entertained  two  thousand  years  ago.  Thus  the  dogma 
of  the  immutability  of  material  species  can  no  longer  be 
upheld.  The  chemical  elements  are  subject  to  the  ravages 
of  time,  and  engender,  through  their  decay,  other  sub- 
stances equally  entitled,  to  all  seeming,  with  themselves,  to 
be  described  as  "elementary."  These  processes,  however, 
which  the  alchemists  of  old  sought  to  command,  we  are  con- 
tent to  observe.  They  will  not  be  hurried  or  controlled; 
they  "gang  their  ain  gate,"  irrespectively  of  laboratory 
conditions ;  all  that  can  be  done  is  to  study  the  modes,  and 
measure  the  rate  of  their  undeviable  advance.  A  few 
buoyant  speculators  are,  indeed,  to  be  found  who  forecast 
the  provision  of  means  to  regulate  at  will,  and  accelerate 
indefinitely,  radio-active  transformations.  When  they  be- 
come available,  the  new  alchemy  will  be  a  working  concern, 
perhaps  even  a  profitable  branch  of  business.  But  for  the 
present,  Nature  keeps  the  management  of  this  particular 
department  entirely  in  her  own  hands.  Man  looks  on  with 
hungry  eyes,  but  his  interference  is  barred  out. 

The  history  of  alchemy  is  one  long  mystification.  It 
deals  largely  with  fictitious  personages.  Of  others,  who  did 
really  "walk  about  the  orb"  in  the  close  company  of  "fool- 
ery," it  narrates  the  apocryphal  adventures.  Its  leading 
authorities  are  mythical.  Illustrious  names  are  audaciously 
employed  to  lend  some  color  of  authenticity  to  its  menda- 
cious annals.  These  form,  indeed,  a  jungle  of  fraud  and 
falsehood.  What  was  true  in  them  was  often  purposely 
obscured,  since  the  arcana  of  the  "great  art"  were  too 
sacred  to  be  openly  divulged.  Its  hierophants  were  veiled 
in  shadow ;  its  origin  was  indicated  by  dim  traditions,  trans- 
mitted by  writers  acquiescent  and  uncritical,  if  not  un- 
candid. 

M.  Berthelot,  in  the  work  quoted  at  the  head  of  this  arti- 


OLD  AND  NEW  ALCHEMY  247 

cle,  has  done  what  was  possible  to  elucidate  the  obscurity. 
His  diligent  labors  have  brought  many  confused  facts  and 
assertions  into  their  proper  sequence,  so  that  we  can  now, 
at  least,  partially  understand  how  the  fanatics,  knaves,  and 
dupes  of  Gnostic  Egypt  came  by  their  mysterious  tenets. 
The  superstitions  and  opinions  they  embodied  proceeded 
from  various  sources,  and  primarily  from  Babylonia,  the 
hotbed  of  occultism.  The  walls  of  Ecbatana,  as  described 
by  Herodotus,1  illustrate  the  connection.  They  were  seven- 
fold, and  vario-tinted,  the  five  outer  circuits  being  embel- 
lished with  the  colors  distinctive  of  the  several  planets, 
while  the  inner  ramparts  glittered  in  gold  and  silver  to 
represent  the  sun  and  moon.  Thus,  the  combined  arrange- 
ment, like  the  seven-storied  temple  of  Nebo  at  Borsippa, 
typified  the  majestic  succession  of  the  celestial  spheres. 
Now  the  planets,  no  less  than  the  sun  and  moon,  claimed 
symbolical  metals.  Lead  was  appropriated  to  Saturn,  tin 
to  Jupiter,  iron  to  Mars,  copper  to  Venus,  and  quicksilver 
(after  its  full  acquaintance  was  made)  to  Mercury.  And 
the  relationship  was  looked  upon  as  intimate  and  real. 
Each  metal  was  not  only  the  client,  but,  in  a  sense,  the  off- 
spring of  a  fostering  heavenly  body.  It  grew  in  the  bowels 
of  the  earth  under  its  influence ;  it  derived  from  it  special 
affinities  and  magical  properties;  it  incorporated  the  sub- 
sensual  action  of  a  celestial  operative  power.  That  the 
metals,  then  few  and  scarce,  should  be  regarded  with  rever- 
ence is  hardly  to  be  wondered  at.  They  were  obtained 
with  difficulty  and  brought  from  afar;  they  came  forth 
from  the  fiercest  ordeal  by  fire  purified  and  vivified;  they 
approved  themselves  in  sundry  ways  as  indispensable 
civilizing  agents. 

The  visionary  metallurgy  of  Babylonia  had  its  practical 
counterpart  in  Egypt.  There  the  arts  of  smelting  ore  and 
of  modifying  and  manipulating  the  products  established 
their  headquarters.  Ptah  of  Memphis  was  a  highly  efficient 

!Book  I,  cap.  98. 


248  MODERN  SCIENCE  READER 

divinity,  far  better  skilled  in  his  trade  than  the  halting 
Olympian  of  the  "Iliad."  The  Word  "chemistry,"  which 
probably  perpetuates  an  old  appellation  for  the  Nile  coun- 
try, was  denned  by  Suidas  in  the  eleventh  century  as  the 
art  of  making  gold  and  silver;  and  the  feasibility  of  such 
achievements  was  intimated  by  early  experiments  with  a 
natural  alloy.  Asem  (translated  by  the  Oeeks  elektros, 
"shining")  figures  prominently  in  the  Egyptian  records; 
it  was  produced  artificially,  held  a  high  place  in  public 
estimation,  and  so  late  as  the  fifth  century  A.D.  was  still  by 
Olympiodorus  assigned  to  the  planet  Jupiter  as  his  repre- 
sentative metal.  Homer  employed  electrum  in  the  decora- 
tion of  the  palace  at  Sparta,1  the  renowned  owners  of  which 
—no  others  than  Menelaus  and  Helen— having  recently 
arrived  from  Egypt,  had  presumably  brought  in  their  train 
some  Egyptian  craftsmen.  Hesiod  made  it  the  ground- 
work of  the  Shield  of  Hercules;  and  many  of  the  objects 
excavated  at  Mycenae  and  Hissarlik  are  composed  of  just 
the  same  kind  of  "white  gold"  offered  by  Croesus  to  the 
Delphian  Treasury.  With  the  lapse  of  centuries,  however, 
its  vogue  declined ;  the  yellow  gold  of  Osiris  was  preferred 
to  the  blanched  metal  sacred  to  Isis ;  and  the  planetary  ties 
of  electrum  were  finally  severed  when  mercury,  imported 
by  the  Carthaginians  from  the  mines  of  Baetica,  became 
available  for  its  replacement. 

It  had,  nevertheless,  done  its  work.  Its  hybrid  nature, 
its  mixed  qualities,  the  experienced  practicability  of  endow- 
ing silver  with  some  of  the  properties  of  gold,  started  the 
long  tradition  of  alchemistic  illusion  and  imposture.  Nor 
was  the  case  of  electrum  solitary.  Many  alloys  were  known 
which  seemed  indistinguishable  from  pure  metals,  and  the 
graduated  changes  in  their  aspect  and  nature  due  to  varia- 
tions in  their  composition  were  explained  on  the  crude 
transmutational  theory.  Technological  practice,  then,  en- 

^Isewhere  in  the  Odyssey,  ^Ae/crpos  certainly  means  amber;  but 
a  metallic  substance  is  clearly  indicated  in  the  passage  above  referred 
to. 


OLD  AND  NEW  ALCHEMY  249 

couraged  belief  in  the  mutual  convertibility  of  the  "strange 
and  rare ' '  substances  secreted,  as  if  through  some  dim  vital 
process,  by  the  earth  under  favor  of  the  spheres.  There 
appeared,  for  instance,  to  be  no  reason,  on  the  face  of 
things,  why  lead  should  not  be  ennobled  into  silver  by  the 
cleansing  action  of  fire,  even  as  electrum  was  refined  into 
gold,  and  iron,  strong  and  lustrous,  was  elicited  from  dull 
earthy  matter. 

The  transcendental  hopes  of  Egyptian  artificers  were 
further  raised  and  stimulated  by  the  vague  speculations  of 
Greek  philosophers.  Empedocles,  vanishing  amid  the 
flames  of  Etna,  left  behind  him  the  long-lived  doctrine  of 
the  four  elements,  or  "roots  of  things."  The  varieties  of 
matter,  in  his  view,  depended  upon  the  variety  of  their 
composition  out  of  earth,  water,  air,  and  fire.  Moreover, 
the  proportions  of  these  admixtures  were  not  supposed  to 
be  determined  inexorably,  once  for  all.  Expedients  might 
be  found  for  their  arbitrary  modification.  But  here  a  log- 
ical difficulty  came  in.  The  elements  imparted  quality,  not 
substance.  Opposed  by  their  qualities,  they  could  not 
be  opposed  in  substance;1  for  substance  is  one,  although 
qualities  are  many.  And  qualities,  to  exist,  must  be  incor- 
porated. Aristotle  evaded  the  crux  by  inventing  a  fifth  ele- 
ment to  serve  as  a  basis  for  the  rest,  and  his  "quintessence" 
has,  in  more  ways  than  one,  obtained  a  kind  of  warrant 
from  modern  science.  But  the  immediate  importance  of 
its  introduction  was  that  it  availed  to  complete,  and  very 
satisfactorily  to  complete,  the  antique  theory  of  matter. 
The  hypothesis,  in  its  finished  shape,  assumed  a  materia 
prima  ("potential  matter,"  in  Verulam's  phrase)  of  inde- 
terminate character,  an  elusive,  and  barely  conceivable 
essence,  and  gave  it  actuality  by  the  addition,  in  suitable 
measure,  of  a  crowd  of  differentiating  properties— hardness, 
color,  weight,  malleability,  brittleness  or  toughness,  and  so 
on.  The  scheme  is  frankly  metaphysical ;  it  deals  through- 

'M.  Berthelot,  Revue  des  Deux  Mondes,  September  1,  1893,  page 
322. 


250  MODERN  SCIENCE  READER 

out  with  abstractions ;  there  is  scarcely  a  point  at  which  it 
touches  reality;  yet  it  finds  a  sort  of  verification  in  the 
delicate  experimental  results  secured  at  the  Royal  Institu- 
tion and  the  Cavendish  Laboratory.  An  "Urstoff"  is  im- 
plied, nay,  insisted  upon  by  an  array  of  well-ascertained 
facts.  Sir  William  Crookes  identified  it,  a  quarter  of  a  cen- 
tury ago,  with  the  "radiant  matter"  in  his  vacuum-tubes. 
It  escapes  irresistibly  from  certain  substances;  imprisoned 
and  bound  in  the  fetters  of  some  mysterious  attraction, 
it  constitutes  all.  In  the  free  state  it  is  matter — if  the 
name  should  be  applied  to  it  at  all— reduced  to  the  ranks, 
generalized,  stripped  of  its  distinctions,  the  same  from 
whatever  source  derived;  it  is  matter  in  potency,  rather 
than  in  act,  intangible,  inaccessible  to  sense-perception, 
probably  indifferent  to  the  solicitations  of  gravity.  Critic- 
ally considered,  it  is  found  to  consist  of  countless  swarms 
of  "electrons,"  traveling  with  prodigious  speed;  and  out 
of  electrons,  diversely  aggregated,  the  chemical  units  or 
atoms  of  ordinary  matter  are  apparently  built  up.  Elec- 
trons may  then  fairly  be  regarded  as  the  modern  equiva- 
lent of  the  formless  "protyle"  of  Greek  thinkers. 

The  dogmas  of  the  fundamental  unity  of  matter,  and  of 
the  "accidental"  character  of  its  sorts  and  species,  evi- 
dently provided  a  rational  justification  for  the  toils  of  al- 
chemists. But  much  more  was  needed  to  give  their  art  the 
vigorous  vitality,  which  enabled  it,  during  twelve  hundred 
years,  to  withstand  the  blasts  and  counterblasts  of  opinion. 
It  lived  and  throve,  not  because  of  the  truths  which  it 
misrepresented,  but  in  virtue  of  the  greed  of  gain  which 
it  encouraged,  and  the  frauds,  half  visionary,  half  vulgar, 
by  which  its  practice  was  sheltered  and  surrounded.  Al- 
chemy was  from  the  first  intertwined  with  the  varied 
forms  of  occult  belief  which  crept  westward,  through 
Alexandria,  from  the  valley  of  the  Euphrates  in  the  early 
centuries  of  our  era.  Egypt  in  those  days  swarmed  with 
Gnostics,  and  Gnosticism  was  in  close  alliance  with  every 
form  of  Oriental  superstition.  Pseudo-sciences,  accordingly, 


OLD  AND  NEW  ALCHEMY  251 

developed,  as  in  a  forcing-house,  under  its  influence,  appro- 
priating authority  by  the  forgery  of  great  names,  and 
acquiring  popularity  through  facile  appeals  to  credulity 
and  cupidity.  "Populus  vult  decipi;  decipiatur,"  will 
always  be  the  mot  d'ordre  of  demagogues  and  charlatans. 

Hermes  Trismegistus,  reputed  to  be  the  first  alchemistic 
author,  was  a  fit  eponym  of  the  "hermetic  philosophy." 
The  books  attributed  to  him  were  numerous,  and  highly 
cryptic;  but  they  were  held  sacred,  and  from  their  dicta 
there  was  no  appeal.  His  identity,  in  fact,  merged  into 
that  of  Thoth,  the  ibis-headed  deity  of  Hermopolis,  and  the 
example  of  pseudonymous  authorship  set  in  his  case  was 
extensively  followed  to  the  bewilderment  of  posterity.  The 
classics  of  alchemistic  literature  are,  more  often  than  not, 
apocryphal ;  their  alleged  authors  are  simulacra.  Thus  the 
Archpriest  John,  the  successor  of  Hermes,  seemed  by  his 
evasiveness  to  prefigure  the  slippery  personality  of  his 
Abyssinian  namesake.  Democritus  of  Abdera,  who  came 
next,  although  endowed,  as  a  philosopher,  with  the  full 
Cartesian  certainty  of  his  own  existence,  played  a  purely 
fictitious  part  in  hermetic  tradition.  His  supposed  sayings 
proceeded  from  his  mouth  by  a  trick,  so  to  speak,  of  ventril- 
oquism. One  of  them,  reported  by  Julius  Firmicus,  has 
a  curious  Baconian  ring.  The  famous  aphorism  of  the 
Novum  Organum,  "Natura  non  nisi  parendo  vincitur," 
was  preluded  by  the  (so-called)  Democritean  maxim,  "Na- 
tura,  alia  a  natura  vincitur, ' '  signifying  that  man  can  only 
indirectly  control  the  operations  of  nature  by  providing 
opportunities  for  their  working  along  the  lines  of  his 
choice.  Bacon's  felicitous  phrase  thus  happily  rescued 
from  oblivion  a  derelict  sentence  of  illuminative  import. 

Democritus  was  said  to  have  received  instruction  in  the 
spagyric  art  from  Ostanes  the  Mede,  classed  with  Zoroaster 
by  St.  Augustine.  Under  the  auspices  of  this  mythical 
personage,  and  described  by  him  in  an  imaginary  treatise, 
the  elixir  vitae  made  its  entry  on  the  scene.  The  association 
is  memorable  as  indicating  the  Chaldean  origin  of  the 


252  MODERN  SCIENCE  READER 

''divine  fluid"  which  became  an  integral  part  of  every 
full-blown  adept's  stock-in-trade.  Later  on  the  fluid  was 
defined  to  be  "potable  gold";  and  the  obscure  but  persist- 
ent relationship  between  the  transmutation  of  metals  and 
the  cure  of  human  ills  was  primitively  emphasized  by  the 
inclusion  of  the  Egyptian  Cnuphis,  the  healing  "soul  of  the 
world,"  among  leading  lights  of  the  art,  under  the  alias 
of  Agathodemon. 

Early  lists  of  goldmakers  were  compiled  with  small  re- 
gard to  probability.  They  comprise  the  names  of  Plato, 
Aristotle,  Heracleitus,  Porphyry,  the  Emperor  Heraclius, 
and  Cleopatra,  the  last  entry  being  due  to  a  confusion  of 
designations  between  her  of  the  "bold  black  eyes"  and  a 
genuine  artist  of  that  name.  Another  female  alchemist 
was  the  supposed  inventor  of  the  bain-marie,  Mary  the 
Jewess.  Her  co-religionists  at  Alexandria  were  strongly 
imbued  with  the  mysticism  of  metallurgy ;  the  related  doc- 
trines had  an  unmistakable  Jewish  complexion,  and  the 
Cabbala  was  pored  over  by  their  adherents  no  less  atten- 
tively and  devoutly  than  the  works  of  Trismegistus  himself. 

The  first  historical  report  of  an  experiment  in  transmu- 
tation has  been  handed  down  by  Pliny  the  Elder.1  Caligula 
was  the  experimenter.  Hoping  to  allay  the  gold-hunger 
which  has  not  yet  ceased  to  gnaw  at  the  vitals  of  the  sons 
of  Adam,  he  built  a  furnace,  and  caused  a  quantity  of 
orpiment  to  be  calcined.  The  result  did  not  come  up  to 
his  expectations;  king's  yellow  (trisulphid  of  arsenic), 
for  all  its  deceptive  glitter,  did  not  prove  to  be  "pay- 
gravel  ' ' ;  the  outlay  exceeded  the  intake,  and  the  ruler  who 
made  his  horse  consul  of  Rome  was,  nevertheless,  sane 
enough  to  withdraw  his  capital  from  a  losing  business.  A 
later  emperor,  Anastasius  of  Byzantium,  sent  the  proto- 
chemist,  Johannes  Isthmius,  to  end  his  fraudulent  career 
in  the  fortress  of  Petra.  Pseudo-science,  too,  has  its 
"martyrs."  But  the  tide  of  folly  rose  with  the  march  of 
time,  and  both  in  France  and  England,  in  the  fifteenth 

*M.  Berthelot,  Les  Origines  de  I'Alchimie,  page  69, 


OLD  AND  NEW  ALCHEMY  253 

century,  the  coinage  was  debased,  with  royal  assent,  by 
claimants  to  the  possession  of  the  " great  secret."1 

From  the  "house  of  Saturn,"  where  it  still  lingered,  by 
a  belated  association,  in  the  verses  of  Firmicus  Maternus 
(fourth  century  A.D.),  alchemy  was  early  transferred  to 
the  "house  of  Mercury."  This  is  a  figurative  way  of  say- 
ing that  quicksilver  was  substituted  for  lead  as  the  sub- 
stratum of  its  operations.  The  choice  had  originally  fallen 
upon  lead,  because  of  its  affinity  to  silver— an  affinity  pos- 
sibly of  far-reaching  import ;  but  it  could  not  hold  its  own 
against  the  new  metal,  spoken  of  by  Theophrastus  about 
300  B.C.  as  "liquid  silver."  An  ideal  recipient  for  the 
"powder  of  projection,"  it  very  soon  displaced  every 
other.  It  was  not  all-sufficing,  but  it  was  indispensable. 
Bricks  might  be  made  without  straw  more  easily  than  the 
precious  metals  without  mercury.  Recipes  for  its  subtil- 
ization,  its  "fixation,"  its  coloration,  abound  in  alchemistic 
treatises.  They  are  for  the  most  part  unintelligible,  espe- 
cially when  introduced  with  promises  of  transparent  can- 
dor ;  for  adepts  wrote,  not  to  disclose  secrets,  but  to  enhance 
the  reputation  of  their  depositaries,  and  they  were  skilled 
in  darkening  counsel,  and  in  taking  while  they  appeared 
to  give.  In  a  moment  of  exaltation,  Raymond  Lully  (or 
rather,  a  personator  of  the  "Doctor  Illuminatissimus")  is 
said  to  have  proclaimed:  "Mare  tingerem,  si  mercurius 
esset!".  tingere  signifying,  in  technical  phraseology,  to 
transmute ;  the  method,  however,  to  be  employed  in  the  con- 
templated gigantesque  performance  he  was  prudent  enough 
to  leave  in  obscurity. 

The  Alexandrian  school  of  science  and  of  thought,  al- 
ready degraded  by  mysticism,  received  a  crushing  blow 
through  the  destruction  of  the  Serapeum  in  391  A.D.  Its 
teachings  were,  nevertheless,  propagated  far  and  wide; 
those  who  inculcated  them  still  led  the  van ;  and  Byzantium 
received  many  of  the  scattered  elements  of  Graeco-Egyptian 

1E.  von  Meyer,  A  History  of  Chemistry,  third  English  edition, 
page  35. 


254  MODERN  SCIENCE  READER 

culture.  Alchemistic  principles  especially  flourished  rankly 
within  the  congenial  precincts  of  New  Rome.  They  en- 
listed many  adherents  and  encountered  few  opponents,  their 
truth  being  (it  would  seem)  tacitly  admitted  even  by  those 
who  sought  no  profit  from  their  momentous  consequences. 
After  the  Hegira,  the  Arabs  seized  the  scepter  of  learning, 
and  Bagdad  far  and  away  outbid  Byzantium.  The  fol- 
lowers of  the  Prophet,  no  less  keen  for  knowledge  than  for 
conquest,  assimilated  indiscriminately  everything  cogni- 
zable by  the  mind  of  man  that  came  in  their  way,  and  hur- 
ried down  blind  alleys  as  eagerly  as  along  open  roads. 
They  made  ideal  adepts,  and  carried  acquaintance  with 
the  wonder-working  Magisterium  with  them  to  Spain, 
whence  it  spread  to  the  courts,  universities,  monasteries, 
and  market-places  of  medieval  Europe.  The  visions  of 
perennial  wealth  and  health  which  it  engendered  kindled 
the  imaginations  of  the  ignorant;  they  admirably  served 
the  purposes  of  the  diversified  brood  of  mystery-mongers; 
kings  and  princes  hoped  to  raise  revenues  ad  libitum 
through  the  metamorphic  action  of  their  croslets  and  alem- 
bics; and  the  possibility  of  so  doing  received  the  sanction 
of  the  highest  intellects.  All  the  known  analogies  of  nature 
seemed,  five  or  six  centuries  ago,  to  justify  the  conviction 
that  metals  were  transformable.  It  ran  counter  to  no 
ascertained  or  imaginable  law  of  nature ;  it  rested  upon  no 
extravagant  assumptions.  The  sought-for  changes,  looked 
at  dispassionately,  might  be  thought  easier  of  realization 
than  the  processes  of  reduction,  by  which  lumps  of  stone 
and  clay  assumed  the  properties  of  iron,  copper,  or  mercury. 
Plausible  in  itself,  alchemistic  doctrine  was  further  recom- 
mended by  a  choir  of  consonant  authorities.  Antiquity 
almost  unanimously  enforced  it ;  Eastern  sages,  profoundly 
versed  in  the  arcana  of  nature  and  art,  were  said  to  have 
adopted  it;  and  the  spurious  character  of  the  evidence  al- 
leged in  its  support  was  a  matter  of  indifference  in  that 
uncritical  age.  Authentic  or  apocryphal,  the  names  and 
maxims  arrayed  in  favor  of  the  spagyric  philosophy  availed 


OLD  AND  NEW  ALCHEMY  255 

equally  to  silence  doubts.  Very  few  expressed  any.  One 
of  the  rare  skeptics  on  the  subject,  however,  was  the  actual 
Raymond  Lully,  a  Spanish  monk  stoned  to  death  by  the 
Moors  of  Africa  in  1315,  some  three  lustres  before  the  date 
of  the  alchemistic  writings  attributed  to  him.  Yet  nearly 
all  his  eminent  contemporaries  and  predecessors  took  an 
opposite  view.  The  noble  figures  of  Albert  the  Great  and 
of  St.  Thomas  Aquinas  tower  above  the  ranks  of  the  Dbmin- 
icans  in  the  thirteenth  century,  and  both  admitted  without 
hesitation  the  asserted  facts  of  transmutation.  Roger 
Bacon  passed  for  an  adept ;  but  popular  fancy  ascribed  to 
him  many  faculties  never  owned  by  him,  and  his  metallurgic 
power,  too,  is  perhaps  legendary.  However  this  may  be, 
he  thought  it  worth  while  to  discuss,  in  a  special  treatise, 
designated  "Speculum  Alchimiae"1  the  fabrication  and 
properties  of  the  "citrine  body,"  called  by  others  the 
"philosopher's  stone,"  or  "grand  magisteriwn."  He  did 
not  minimize  its  marvels.  It  had  efficacy,  in  his  opinion, 
not  only  to  transform  into  gold  one  million  times  its  own 
weight  of  base  metal,  but  also,  if  administered  in  the  form 
of  a  drug,  to  prolong  human  life.  Nor  was  he  exceptionally 
sanguine.  Votaries  were  to  be  found,  more  enthusiastic 
or  more  deeply  initiated,  who  taught  that  the  elixir  could 
impart  as  well  as  lengthen  life. 

Despite  this  riot  of  unreason,  knowledge  intermittently 
advanced.  Valuable  items  of  information  presented  them- 
selves unsought,  and  chemistry  began  dimly  to  shape  itself 
in  the  foggy  atmosphere  of  occult  persuasions.  Alcohol 
was  distilled ;  acquaintance  was  made  with  the  uses  and 
peculiarities  of  metallic  zinc,  arsenic,  and  antimony;  cor- 
rosive sublimate,  red  precipitate,  oil  of  vitriol  (sulphuric 
acid),  and  aqua  fortis  (nitric  acid),  took  their  places  in 
the  laboratory;  while  the  resources  of  the  pharmacopoeia 
were,  from  many  quarters,  materially  enlarged.  The  ap- 
portionment of  credit,  however,  for  these  sundry  inventions 
is  impossible.  Evasive  or  misleading  records  completely 
'H.  Kopp,  Die  AlcMmie,  &c.,  page  23. 


256  MODERN  SCIENCE  READER 

shroud  their  origin.  Medieval  discoverers,  far  from  put- 
ting forward  eager  claims  to  priority  in  their  innovations, 
sought  to  give  them  eclat  by  passing  them  off  as  antique. 
Enveloping  them  in  the  glamour  of  an  established  reputa- 
tion, they  fired  their  darts,  so  to  speak,  from  under  the 
shield  of  some  Ajax  of  their  choice.  The  early  stages  of 
chemical  history  hence  evade  exact  inquiry. 

The  circumstance  is  singular  and  characteristic  that  the 
two  latest  masters  in  alchemy,  like  the  majority  of  their 
far-off  precursors,  were  elaborate  impostors.  Abu  Musa 
Djabir  ben  Hal j an,  currently  known  as  Geber,  had  a  posi- 
tion assigned  to  him  in  hermetic  science  not  inferior  to  that 
rightly  occupied  by  Hipparchus  in  the  history  of  astronomy. 
His  writings  were  regarded  as  canonical;  his  decisions  as 
indisputable.  Rhazes  and  Avicenna  designated  him 
•magister  magistrorum  •  Cardan  extolled  him  as  one  of  the 
twelve  greatest  geniuses  the  world  had  seen,  and  he  even 
now  enjoys  a  certain  nebulous  fame.  Yet  his  personality 
was  never -quite  clearly  defined.  According  to  Abulfeda, 
an  Arab  geographer  of  the  fourteenth  century,  he  was  a 
native  of  Harar  in  Mesopotamia ;  his  birthplace  is  elsewhere 
located  in  Khorassan;  Leo  Africanus  asserted  him  to  have 
been  a  renegade  Greek.  He  is  variously  spoken  of  as  a 
Syrian  disciple  of  Khaled,  as  an  Indian  prince,  and  as  hav- 
ing died  at  Seville  in  the  year  765.  An  astronomer  of  the 
same  name,  who  genuinely  flourished  in  Spain  during  the 
twelfth  century,  has  frequently  been  confounded  with  him, 
and  he  has  been  credited  with  the  invention  of  algebra. 
Nothing  is  certain  except  the  spuriousness  of  the  numerous 
tracts  and  essays  circulated  under  his  name.  This  has 
been  proved  by  M.  Berthelot  from  the  most  convincing 
internal  evidence.1  By  a  sort  of  regenerative  process,  the 
works  and  their  imaginary  author  acquired  secular  renown. 
They  mutually  reinforced  one  another's  prestige;  for  the 
accumulated  productions  of  successive  forgers  had  at  least 
merit  enough  to  add  continually  to  the  wonder  that  a  single 
1La  Chlmie  au  Moyen-age,  t.  i.  page  231. 


OLD  AND  NEW  ALCHEMY  257 

man  should  have  been  at  once  so  profuse  and  so  profound. 
This  structure  of  falsehood  has,  indeed,  a  nucleus  of  truth. 
M.  Berthelot,  at  any  rate,  believes  that  he  can  recognize 
such  a  nucleus  in  some  Arabic  manuscripts  preserved  in 
the  public  libraries  of  Paris  and  Leyden.  They  are  suffi- 
ciently primitive  in  purport  to  have  been  composed  in  the 
eighth  century;  their  style  is  of  the  mystical  kind  proper 
to  occultists ;  they  lay  stress  on  the  planetary  relationships 
of  metals,  and,  in  fact,  show  no  appreciable  deviation  from 
the  Byzantine  standpoint.  They  might  then  very  well  have 
been  indited  by  a  real  though  insignificant  Geber,  ampli- 
fied by  subsequent  accretions  to  the  imposing  dimensions  of 
the  author  of  the  Summa  Perfections.  Basilius  Valen- 
tinus,  on  the  other  hand,  the  final  product  of  the  alchemistic 
tradition,  appears  to  have  been  a  pure  and  gratuitous  inven- 
tion. The  successful  exertion  of  the  mythopoeic  faculty  by 
which  he  came  into  being  took  effect  in  the  full  daylight  of 
the  seventeenth  century.  He  was  stated  to  have  been  born 
in  the  Upper  Rhenish  provinces  late  in  the  fourteenth 
century,  to  have  traveled  long  in  Spain,  England,  and  the 
Low  Countries,  and  to  have  ultimately  entered  a  Benedict- 
ine convent  somewhere  in  Germany.  His  rumored  learning 
excited  the  curiosity  of  the  Emperor  Maximilian,  who 
vainly  attempted  to  localize  his  retreat.  It  was  only  after 
a  hundred  years  had  passed  that  the  obscurity  seemed  to 
dissipate.  A  certain  Johannes  Tholde  published  at  Frank- 
enhausen,  early  in  the  seventeenth  century,  a  collection  of 
works  by  the  author,  or  authors,  styled  Basilius  Valentinus. 
They  were  remarkable  enough  to  justify  his  high  reputa- 
tion. They  showed  him  to  have  possessed  great  technical 
skill;  they  completed  the  theory  of  the  composition  of 
metals  by  adding  "salt"  (any  principle  of  solidification) 
to  the  mercury  and  sulphur  previously  admitted  as  their 
ingredients;  while  a  tract  entitled  "The  Triumphal  Car 
of  Antimony"  described  several  preparations  of  that  metal 
clearly  intended  for  internal  use.  These  recipes  are  con- 
sidered to  have  paved  the  way  for  the  advent  of  true  medic- 
17 


258  MODERN  SCIENCE  READER 

inal  chemistry.1  Even  about  the  philosopher's  stone  he  was 
comparatively  explicit,  and  his  dicta  were  received  as  ora- 
cles. Yet  their  connection  with  Basilius  Valentinus  appeared 
to  many  uncertain.  Whence,  it  might  be  asked,  did  the 
manuscripts  edited  by  Tholde  come  from?  The  question 
was  answered  in  a  singular  fashion.  Toward  the  middle 
of  the  century,  stories  coming  from  nowhere  in  particular 
began  to  be  circulated  to  the  effect  that  the  doubtful 
writings  had  been  found,  according  to  one  version,  under 
the  high  altar  of  the  Benedictine  convent  at  Erfurt,  accord- 
ing to  another,  inside  one  of  its  columns,  which  a  flash  of 
lightning  had  split  open.  Then,  in  1675,  J.  M.  Gudenus 
announced,  as  the  upshot  of  inquiries  made  on  the  spot, 
that  Basilius  Valentinus,  the  champion  of  antimony,  and 
the  inventor  of  the  trinal  constitution  of  matter,  had  worn 
the  cowl  at  Erfurt  in  1413,  and  had  there  surreptitiously 
bequeathed  his  mysterious  fame  to  posterity.  There  is  lit- 
tle doubt  that  he  was  mistaken;  but  the  solution  of  the 
problem  offered  by  identifying  Johannes  Tholde  with 
Basilius  Valentinus  is  not  the  most  probable.  The  suppo- 
sition of  multiple  authorship  is  to  be  preferred.  Tholde, 
one  may  believe,  collected  scattered  writings  already  par- 
tially known.  He  gave,  in  a  manner,  epic  importance  to 
detached  lays. 

They  could  scarcely  have  been  known,  except  by  report, 
to  John  Dee  of  Mortlake,  crystal-gazer  and  alchemist. 
Deluded  himself,  and  the  cause  of  manifold  delusions  to 
others,  he  submerged  his  originally  fine  faculties  in  a  quag- 
mire of  baneful  figments.  Queen  Elizabeth  wished  to  make 
him  a  bishop,  and  invoked  his  aid  to  avert  harmful  effects 
from  malicious  injury  done  with  a  pin  to  a  waxen  image  of 
her  royal  person,  found  in  Lincoln's  Inn  Fields  in  1577. 
The  appearance,  about  the  same  time,  of  a  great  comet 
further  excited  her  alarm;  which  having  allayed,  he  trav- 
eled abroad  in  quest  of  remedies  for  her  tooth-ache  and 
rheumatic  pains.  Later  he  became  the  dupe  of  Edward 
*E.  von  Meyer,  History  of  Chemistry,  page  36. 


OLD  AND  NEW  ALCHEMY  259 

Kelley,  a  clever  knave,  who  served  as  his  spiritualistic 
medium  and  alchemistic  instructor.  Their  joint  gold- 
making  career  was  not  wholly  unprosperous.  Albert  Laski, 
a  credulous  and  impecunious  foreign  prince,  hoped  to  re- 
trieve his  broken  fortunes  through  the  medium  of  the 
philosopher's  stone.  Leicester  introduced  him  in  1583  to 
Dee,  who  entertained  him  at  Mortlake  at  the  Queen's  ex- 
pense, convinced  him  of  his  recondite  powers,  and  at  his 
request  followed  him,  in  the  company  of  Kelley,  to  the 
castle  of  Laskoe,  near  Cracow.  There  they  wasted  costly 
materials  until  their  host,  at  the  end  of  his  resources  and 
of  his  patience,  despatched  them  to  Prague.  Expelled 
thence  as  sorcerers,  and  refused  admittance  to  Erfurt,  they 
were  assigned  by  Count  Kosenberg  in  1586  a  stately  resi- 
dence at  Tribau  in  Bohemia.  Dee's  globe  of  smoky  glass 
and  mirror  of  cannel  coal  were  now  again  in  requisition  for 
the  purposes  of  spiritualistic  evocations,  and  Kelley,  hav- 
ing transmuted  into  gold  a  section  of  a  warming-pan,  sent 
it  in  triumph  to  Queen  Elizabeth;  while  Arthur  Dee  and 
young  Rosenberg  played  at  quoits  (we  are  told)  with 
pieces  of  gold  and  silver  made  by  projection.  The  reputed 
source  of  this  Lydian  opulence  was  a  considerable  stock, 
discovered  by  Kelley  amid  the  ruins  of  Glastonbury  Abbey, 
of  the  " stone  of  the  wise."  But  the  partners  inevitably 
fell  out.  Kelley,  who  in  his  golden  days  had  been  knighted, 
it  is  believed,  by  the  Emperor,  was  subsequently  thrown 
into  prison  at  Prague,  and  perished  in  attempting  to  escape 
in  1595.  Dee  returned  in  1589  to  England,  destitute  of 
his  fairy  wealth,  and  lacking  the  means  to  produce  more. 
He,  however,  still  enjoyed  royal  favor;  pensions  and  pre- 
ferments relieved  his  immediate  wants,  and  he  was  ap- 
pointed warden  of  Manchester  College  in  1595.  He 
resigned  the  post  in  1604,  and  died  four  years  later  in 
extreme  penury.  A  half -convinced  charlatan,  he  was  the 
victim  and  the  plaything  of  the  malign  influences  to  which 
he  surrendered  himself. 

Henricus  Cornelius  Agrippa  (1486  to  1535)  and  Aure- 


260  MODERN  SCIENCE  READER 

olus  Philippus  Theophrastus,  commonly  called  Paracelsus, 
were  both  pupils  in  chemistry  of  Trithemius,  Abbot  of 
Spannheim,  and  were  held  to  compete,  on  equal  terms,  for 
the  honorable  title  of  Trismegistus  redivivus.  Eliphas  Levi 
remarked  of  Paracelsus  that  he  had  "divined  more  than  any 
one  without  ever  completely  understanding  anything."1 
The  facts  of  his  life  are  vaguely  known,  having  been 
thickly  overlaid  with  embellishing  legends.  It  is,  neverthe- 
less, fairly  certain  that  he  was  born  at  Einsiedeln,  in 
Switzerland,  in  1493,  as  the  only  child  of  a  well-thought-of 
physician  in  orthodox  practice.  His  son  was  of  a  different 
stamp.  Attracted  in  boyhood  by  the  phantasmagoria  of 
learning,  he  studied  alchemy  in  the  works  of  Isaac  the  Hol- 
lander, and  imbibed  from  them  the  doctrine  of  the  ele- 
mental triad  of  mercury,  sulphur,  and  salt,  which  he  subse- 
quently diffused  and  recommended. 

He  entered  the  University  of  Basle  at  the  age  of  sixteen. 
His  studies  were  desultory,  if  occasionally  intense.  But 
a  cap-and-gown  life  was  not  for  him,  he  had  the  "hungry 
heart"  of  the  born  traveler,  and  in  1516  he  set  out  to 
tramp  the  "open  road"  that  has  many  turnings,  but  no 
terminus.  Supporting  himself  as  he  went  along  by  casting 
horoscopes,  fortune-telling,  cheiromancy,  and  the  like,  he 
left  no  European  country  unvisited.  Not  even  Russia, 
whence  he  was  fabled  to  have  reached  the  court  of  the  Great 
Cham,  and  to  have  attended  the  son  of  that  shadowy  poten- 
tate on  an  embassy  to  Constantinople.  There  he  acquired, 
if  rumor  spoke  truly,  the  secret  of  the  "double  tincture," 
capable  both  of  lengthening  life  and  of  ennobling  metals; 
and  a  wandering  Arab  made  him  acquainted  with  the 
mysterious  "alcahest,"  or  universal  solvent.  He  learned 
also  the  virtues  of  laudanum,  and  soon  afterward  began  to 
effect  cures,  the  fame  of  which  preceded  him  as  he  strolled 
homeward,  and  secured  for  him,  in  1526,  the  chair  of 
physics  and  surgery  in  his  old  university.  Professorial 

1Histoire  de  la  Magie,  livre  v.  ch.  5.     Quoted  by  A.  E.  Waite,  pref- 
ace to  The  Hermetic  Writings  of  Paracelsus,  1894. 


OLD  AND  NEW  ALCHEMY  261 

dignity,  however,  was  much  to  seek  in  his  behavior.  He 
quarrelled  with  the  municipal  authorities,  or  they  with 
him;  insulted  his  colleagues,  mystified  his  audiences,  and 
incurred  obloquy  by  his  extravagant  self-laudations.  De- 
cried as  a  quack,  and  baited  by  numerous  enemies,  he  with- 
drew at  the  end  of  a  year  from  an  impossible  position,  and 
resumed  vagrancy  in  his  multiple  capacity  of  theosophist, 
faith-healer,  conjurer,  physician,  and  seer.  He  died  on 
September  24,  1541,  at  the  Inn  of  the  White  Horse  in  Salz- 
burg, and  was  buried  under  the  porch  of  the  church  of  St. 
Sebastian.  The  tale  of  his  assassination  by  rival  practi- 
tioners was  set  going  by  Yon  Sommering's  discovery  in 
1815  of  a  fissure  in  his  exhumed  skull,  produced,  quite 
probably  and  harmlessly,  by  a  chance  stroke  of  the  grave- 
digger's  spade.1  His  "long  sword"  became  legendary. 
Its  pommel,  he  himself  asserted,  lodged  his  familiar  spirit, 
and  this  was  interpreted  to  mean  that  it  contained  some 
portion  of  the  "Azoth,"  or  elixir  (perhaps  opium  in  some 
shape),  which  he  used  as  a  remedy  for  disease.  The  crude 
popular  impression  in  the  matter  was  conveyed  by  Samuel 
Butler's  quatrain: 

Bumbastus  kept   a   devil's  bird 

Shut  in  the  pommel  of  his  sword, 

That  taught  him  all  the  cunning  pranks 

Of  past  and  future  mountebanks. 

Hudibras,  Part  II.  canto  3. 

Yet  he  had  real  genius.  His  "bald  pate,"  he  truly  said, 
sheltered  thoughts  that  had  not  dawned  upon  Avicenna,  or 
permeated  the  universities.  They  were,  indeed,  mostly 
fantastic,  those  thoughts  of  his,  but  they  were  often  pro- 
found. A  man  of  science  was  disguised  in  the  bedizenments 
of  wild  folly  that  he  at  times  deliberately  put  on.  He 
attached  to  himself  followers,  such  as  Benedictus  Figulus, 
who  discerned  his  "searching  and  impetuous  soul,"  and  if 
he  contemned  the  would-be  wise,  he  was  liberal  to  the 

^ee  Theophrastus  Paracelsus.  Eine  Tcrltische  Studie.  Von  Fried- 
rich  Mook,  1876;  and  Paracelsus-Forschungen.  Von  E.  Schubert 
and  Karl  Sudhoff,  1889. 


262  MODERN  SCIENCE  READER 

needs  of  the  poor.     His  portrait  bears  the  inscription  com- 
posed by  himself: 

Alterius  ne  sit,  qui  suus  esse  potest. 

He  was  incidentally,  not  exclusively,  an  alchemist. 
Therapeutic  chemistry  ranked  higher  in  his  esteem  than 
metallurgic  chemistry.  Yet  the  creed  of  the  adepts  con- 
tinued to  be  held  widely  and  long.  Robert  Boyle,  one  of 
the  chief  ornaments  of  the  Royal  Society,  firmly  adhered 
to  it;  so  did  Glauber,  Kunkel,  Stahl,  the  prophet  of  phlo- 
giston, and  Boerhaave,  eminent  at  the  University  of  Leyden 
in  the  eighteenth  century.  Helvetius  and  Van  Helmont 
fell  abjectly  into  the  trap  of  the  delusion.  Each  in  turn 
received  from  an  unknown  hand  a  specimen  of  the  philoso- 
pher's stone,  and  each  in  turn  verified  (as  he  supposed) 
its  supramundane  power  for  the  aurification  of  mercury 
or  lead.  Even  the  great  Tycho  Brahe  had  a  narrow  escape. 
It  needed  the  celestial  summons  of  the  new  star  of  1572  to 
rescue  him  from  the  hermetic  slough.  Many  German 
princes,  too,  favored  the  " Divine  art."  Rudolph  II  was 
styled  the  German  Trismegistus ;  John  the  Alchemist, 
Burggrave  of  Nuremberg,  practised  it  in  person ;  Augustus 
I,  Elector  of  Saxony,  and  his  consort  Anna  of  Denmark, 
explored  its  mysteries  in  gorgeous  laboratories.  Later  it 
fell  into  disrepute.  Its  votaries  foregathered  with  the 
brethren  of  the  Rosy  Cross,  and  many  of  them  trod  devious 
and  dangerous  ways.  Some  came  to  tragical  ends.  Alex- 
ander Seton,  author  of  "Novum  Lumen  Chemicum,"  was, 
with  futile  cruelty,  tortured  to  death  at  Dresden  in  1603, 
in  the  hope  of  wringing  from  him  a  golden  secret  which 
he  bequeathed,  probably  in  good  faith,  to  his  Polish  pro- 
tector, Michael  Sendivogius.1  He  had  a  fellow-sufferer, 
after  the  lapse  of  a  century,  in  the  Neapolitan  adept 
Caetano,  surnamed  the  "Conte  Ruggiero,"  who  was  hanged 
at  Berlin  in  1709  on  a  gallows  glittering,  by  a  grim  mock- 
ery, with  gold  tinsel.  Finally,  there  was  the  strange  and 

'A.  E.  Waite,  A  Golden  and  Blessed  Casket  of  Nature's  Marvels, 
by  Benedictus  Figulus,  Preface  to  English  translation. 


OLD  AND  NEW  ALCHEMY  263 

piteous  case  of  James  Price.  He  was  a  man  of  fortune, 
learning,  and  honor;  the  University  of  Oxford  conferred 
upon  him,  in  1782,  a  degree  of  M.D.  expressly  for  his 
"chemical  labors,"  and  he  was  a  distinguished  member  of 
the  Royal  Society.  Unfortunately,  however,  he  followed 
the  chimaera  of  transmutation,  and  described  in  a  book, 
which  was  a  nine  days'  wonder  to  the  gaping  world,  his 
successful  experiments  with  the  white  and  the  red  tinctures 
for  converting  mercury  into  silver  and  gold  respectively. 
Challenged  to  repeat  them  by  the  Royal  Society,  he  failed 
to  do  so,  and  having  swallowed  a  tumbler  full  of  laurel- 
water,  he  died  in  the  presence  of  the  three  delegates  of  that 
body,  in  August,  1783. 1  There  is  little  or  no  doubt  that  his 
brain  had  given  way,  and  that  he  was  the  victim,  either  of 
his  own  delusions  or  of  others'  fraud.  Yet  the  auri  sacra 
fames  was  not  sated.  Frederick  the  Great,  thinking  to 
emulate  Croesus,  at  one  time  kept  a  lady  alchemist,  Frau 
von  Pfuel,  busy  with  powders  and  fluxes  at  Potsdam.  And 
the  Hermetic  Society,  founded  in  1796  by  two  Westphalian 
physicians  of  consideration,  published  its  transactions  and 
avowed  its  purposes  in  the  respectable  columns  of  the 
Deutscher  Reichsanzeiger. 

That  a  cloudy  intuition  of  truth  was  interwoven  with  this 
protracted  history  of  folly  and  fraud,  we  now  at  last  know, 
although  most  imperfectly.  The  discovery  of  radio-active 
transformations  is  of  yesterday.  It  dates  essentially  from 
the  joint  investigations  in  1903  of  Professors  Rutherford 
and  Soddy,  at  the  McGill  University,  Toronto,  on  the  "ema- 
nation" of  thorium,  and  expressly  from  June  7  of  that 
year,  when  Sir  William  Crookes,  in  an  address  delivered 
at  Berlin,  gave  vivid  expression  to  his  doubts  as  to  "the 
permanent  stability  of  matter."  This  is  only  the  begin- 
ning; the  end  is  not  yet  in  view.  A  new  road  has  been 
projected;  but  the  engineering  difficulties  are  numerous 
and  formidable.  To  overcome  them  will  be  the  great 
scientific  work  of  the  twentieth  century. 

dictionary  of  National  Biography,  vol.   xlvi,  page  328. 


264  MODERN  SCIENCE  READER 

The  fundamental  postulate  of  ancient  and  medieval 
alchemy  was  that  metals  are  chemical  compounds.  It  was 
not  an  extravagant  belief ;  the  facts  of  technical  experience 
accorded  with  it;  its  truth  appeared  incontestable  until 
Lavoisier  published,  in  1787,  his  Methode  de  Nomenclature 
Chimique.  A  treatise  on  metallic  dissociation  was  accord- 
ingly adjudged  a  prize  by  the  Copenhagen  Academy  of 
Sciences  in  1780,  and  G.  G.  Kastner,  professor  of  chemistry 
at  the  University  of  Heidelberg,  ignorant  or  negligent  of 
Lavoisier's  work,  suggested  in  1806  the  feasibility  of  fabri- 
cating quicksilver  out  of  phosphorus  and  charcoal.1  The 
integrity  of  the  atom,  on  the  other  hand,  is  the  most  essen- 
tial principle  of  modern  chemistry,  and  metals  are  distinc- 
tively "  elementary  "  in  the  nineteenth-century  sense.  That 
is  to  say,  they  are  indecomposable  by  force  or  skill.  Their 
atoms  are  veritable  chemical  units.  Yet  they  have  long 
been  suspected  to  be  physically  divisible  under  conditions 
different  from  the  ordinary.  They  show  wide  diversities 
in  weight,  the  lead-atom,  for  instance,  being  nearly  thirty 
times  heavier  than  the  lithium  atom.  Moreover,  the  atomic 
weights,  to  the  number  of  nearly  eighty,  fall  into  related 
series,  intimating  the  action,  it  is  thought,  of  some  law  by 
which  indefinitely  small  particles  have  variously  collected 
into  connected  systems.  The  subtlety  and  sensitiveness, 
too,  of  luminous  vibrations,  together  with  the  manifold 
intricacies  of  spectral  effects,  lent  countenance  to  the  opin- 
ion that  atoms  might  be  elaborate  pieces  of  mechanism, 
their  parts  being  probably  in  rapid  motion.  The  paradox- 
ical hypothesis  that  atoms  have  parts  has  now  become  a 
recognized  truth  of  science.  They  are  complex  aggregates, 
and  the  aggregates  are  liable  to  go  to  pieces.  This  is  the 
secret  of  radio-activity.  This  was  the  meaning  of  the 
actinic  effects,  due  to  some  effluvium  from  a  salt  of  uranium, 
detected  by  M.  Henri  Becquerel  in  1896.  They  implicitly 
announced  what  was  little  short  of  a  scientific  revolution. 

How  far  it  will  be  carried  none  can  foretell.  As  yet  we 
*E.  Schultze,  Das  Letzte  Aufflackern  der  Alchemic,  page  42. 


OLD  AND  NEW  ALCHEMY  265 

have  learned  little  more  than  that  some  or  all  of  the  various 
forms  of  matter  spontaneously  decay,  and  give  rise,  in 
decaying,  to  other  forms.  The  three  heaviest  metals,  uran- 
ium, thorium,  and  radium,  are  the  most  conspicuous  possess- 
ors of  these  extraordinary  properties.  Their  intimate 
structure  is  such  as  to  render  them  unstable.  Each  of 
their  atoms  is  the  seat  of  eventually  self-destructive  activi- 
ties. True,  their  waste,  although  unceasing,  is  excessively 
slow.  Radium,  the  shortest-lived  of  the  trio,  needs  about 
1,300  years,  Professor  Rutherford  calculates,1  to  become 
half  disintegrated,  while  30,000  must  elapse  before  the 
earth's  present  stock  is  virtually  exhausted.  Something 
will,  indeed,  be  left;  but  it  will  not  be  radium.  Perhaps 
the  residuum  will  prove  to  be  lead.  Indications  have  been 
gathered  that  radium  is  compounded,  in  a  transcendental 
manner,  of  helium  and  lead.  Helium  unquestionably 
escapes  at  each  stage  of  its  decay,  and  the  conjecture  is 
plausible  that,  after  the  fifth  and  last  emission  of  helium- 
particles,  lead  remains  as  a  caput  mortuum. 

Nor  is  radium  itself  believed  to  be  an  aboriginal  sub- 
stance. For  unless  there  were  a  continuous  source  of  sup- 
ply, the  stock  would  evidently  have  long  ago  become- 
exhausted.  What  perishes  day  by  day  must  day  by  day 
be  renewed,  and  the  renewal  is,  in  this  case,  apparently 
effected  by  the  exorbitantly  slow  transformation  of  uran- 
ium. The  grounds  for  this  view  are:  First,  that  the  two 
metals  never  occur  separately,  uranium  always  holding  a 
percentage  of  radium;  secondly,  that  this  percentage  has 
a  constant  value.  Its  invariability  clearly  results  from  the 
establishment  of  an  equilibrium  between  production  and 
waste.  Radium  is  scarce,  because  it  is  quickly  dissipated. 
It  bears  within  itself  the  seeds  of  destruction.  Solid  in 
appearance,  it  is  in  reality  more  unstable  than  the  thinnest 
air.  Even  the  substantial  preservation  of  its  materials 
is  open  to  doubt.  In  other  words,  there  is  some  proba- 
bility that  many  of  the  particles  flung  out  from  its  dis- 
io- Active  Transformations,  page  176. 


266  MODERN  SCIENCE  READER 

rupted  atoms  cease  to  be  matter  as  ordinarily  understood. 

The  principle  of  the  conservation  of  mass  was  heretofore 
regarded  as  the  corner-stone  of  the  chemical  edifice.  It 
assumed  matter  to  be  indestructible,  and  indestructible  it 
surely  is  by  the  time-honored  methods  of  the  laboratory. 
Decomposition  and  recomposition,  solution  and  precipita- 
tion, fractionation,  distillation,  calcination,  leave  mass 
exactly  what  it  was  before.  Gravity  is  unalterable  so  long 
as  the  atom  remains  intact.  But  the  break-up  of  the  atom 
in  radio-active  processes  lands  us  on  a  totally  different 
plane  of  inquiry.  Atoms  are  composed  of  "electrons"  or 
unit-particles  of  electricity,  linked  together  by  forces  of 
tremendous  power.  When  the  infinitesimally  small,  though 
highly  intricate,  systems  thus  formed  undergo  collapse 
through  some  innate  defect  of  stability,  a  readjustment 
ensues.  Some  of  their  component  electrons  issue  freely 
into  the  ambient  ether;  others  group  themselves  anew  into 
atoms  of  less  heavy  metals ;  others  again  into  helium-atoms. 
But  the  total  resulting  atomic  weight  must  be  less  than  the 
weight  of  the  original,  undecomposed  atom,  in  consequence 
of  the  subtraction  of  escaped  electrons.  Whether  or  no 
electrons  gravitate  is  a  moot  point.  They  possess  inertia; 
yet  appear  to  lie  outside  the  domain  of  the  great  universal 
force.  In  shaking  off  atomic  bonds  they  would  then  cease 
to  gravitate,  and  mass  would  be,  pro  tanto,  diminished.1 
On  the  contrary  supposition,  there  should  be  a  loss,  not  of 
absolute,  but  of  measurable  mass ;  for  electrons,  once  set  at 
large,  are  not  easily  recaptured. 

These  still  obscure,  though  significant  possibilities  illus- 
trate the  radical  change  in  the  views  of  physicists  brought 
to  pass  by  the  investigation  of  radio-activity.  Once  more, 
as  of  old,  the  framework  of  nature  has  come  to  appear 
plastic.  Once  more  we  are  confronted  with  the  quintes- 
sential community  of  material  things.  We  discern  them 
as  built  up  variously  out  of  the  same  sub-elemental  stuff, 
which,  like  the  materia  prima  of  the  ancients,  is  subtilized 
*E.  Rutherford,  Radio- Activity,  second  edition,  page  336. 


OLD  AND  NEW  ALCHEMY  267 

to  the  verge  of  evanescence.  What  we  call  electrons,  in 
short,  our  scientific  ancestors  designated  "protyle"  con- 
ceived of  as  "potentially  all  things,  and  actually  noth- 
ing."1 Modern  protyle  has,  however,  been  captured,  and 
can  be  generated  at  will  by  the  agency  of  electricity.  No 
longer  a  metaphysical  abstraction,  it  advances  definite 
claims  to  a  concrete  if  incomprehensible  existence. 

Elemental  evolution,  in  its  only  cognizable  form,  inverts 
the  course  of  organic  evolution.  For  an  ascent  from 
homogeneity  toward  heterogeneity,  it  substitutes  progress 
by  degradation.  Complex  atoms  are  continually  getting 
reduced  to  a  more  simple  state  through  the  shedding  of 
their  component  electrons.  Moreover,  the  shed  electrons 
for  the  most  part  reconstitute  themselves  into  systems,  and 
enter  upon  independent  atomic  careers.  That  is  to  say, 
there  result,  as  the  permanent  products  of  radio-active 
change,  a  metal  of  inferior  atomic  weight  to  the  metal 
partially  decomposed,  and  a  gas.  Now  the  gas  has  been 
identified  by  its  spectrum  as  helium,  so  named  by  Sir 
Norman  Lockyer  in  1869,  because  of  its  abundant  presence 
near  the  sun.  Until  1895,  when  Sir  William  Ramsay  made 
its  hiding-place  in  clevite  too  hot  to  hold  it,  this  singular 
substance  was  a  mere  cosmic  acquaintance.  The  twelve 
years  since  elapsed,  however,  have  sufficed  to  make  its  prop- 
erties familiar.  They  are  chiefly  negative.  It  has  no 
chemical  affinities ;  a  "  rogue ' '  element,  it  exists  in  isolation 
or  imprisonment ;  it  only  slightly  refracts  light ;  it  is  elec- 
trically neutral ;  it  remains  obstinately  aeriform  at  tempera- 
tures much  below  the  boiling-point  of  hydrogen.  Although 
of  extreme  terrestrial  scarcity,  its  effusion  is  an  unfailing 
concomitant  of  atomic  decay,  and  from  radium  in  partic- 
ular, has  been  proved  to  go  on  without  let  or  hindrance. 
The  atoms  of  helium  are  thus  framed  under  our  eyes.  We 
can  watch  an  element  in  the  making.  But  the  process  is 
usually  far  more  leisurely.  The  evolution  of  metals  is 
largely  a  matter  of  inference.  It  goes  forward  too  slowly 
^Fowler's  Novum  Organum,  page  339,  note  13. 


268  MODEKN  SCIENCE  READER 

to  be  directly  observable.  To  this  rule  there  is,  we  admit, 
one  exception.  The  degradation  of  uranium  into  radium 
has  become  perceptible  even  within  the  brief  span  of  recent 
experimental  inquiry. 

For  the  rest  there  is  room  and  to  spare  for  speculation. 
The  metals  are  very  curiously  interrelated,  both  in  their 
qualities  and  in  their  distribution.  Some  occur  in  almost 
inseparable  companionship.  Among  these  cognate  couples 
are  silver  and  lead.  In  Mr.  Donald  Murray's  words:  "A 
lead  mine  is  a  silver  mine,  and  a  silver  mine  is  a  lead  mine 
all  the  world  over,  and  yet  the  chemical  attraction  between 
silver  and  lead  is  slight,  and  the  two  metals  are  not  suffi- 
ciently common  to  concur  by  chance. ' n  The  inference  was 
irresistible,  and  has  been  reached  by  others,  that  silver  is  a 
disintegration  product  of  lead.  And  it  is  interesting  to 
remember  that  lead,  until  superseded  by  mercury,  was 
accounted  in  alchemistic  theory  the  " mother  of  metals." 
Now  the  persuasion  is  gaining  ground  that  the  supplies  of 
the  various  elements  existing  in  the  earth  are  regulated  by 
the  proportion  between  their  rates  of  development  and 
dissolution.  Elemental  distribution  does  not  show  the 
extreme  inequalities  which  would  stamp  it  as  the  outcome 
of  chance.  The  approximate  constancy  in  the  quantities 
present  in  all  quarters  of  the  globe  of  such  rare  metals  as 
gold,  platinum,  thallium,  indium,  gallium,  and  so  on, 
appears  to  intimate  the  working  of  a  genetic  law.  It  sug- 
gests that  they  are,  in  Professor  Soddy's  phrase,  at  once 
offspring  and  parent  elements  ;2  that  fhey  are  derived  from 
substances  more  highly  elaborated  5  that  they  give  rise,  as 
they  in  turn  spontaneously  decompose,  to  others  less  com- 
plex, the  relative  speed  of  these  ineffably  slow  alterations 
determining  the  amount  of  each  product  found  in  the  earth 
at  a  given  time.  This  remarkable  hypothesis  may  be  veri- 
fied, according  to  Professor  Soddy's  anticipation,  by  the 
discovery  of  occluded  helium  in  antique  gold. 

Thus  physical  science  in  the  twentieth  century  has  been 
1  Nature,  vol.  Ixxiii,  page  125.  2  Hid,  page  151. 


OLD  AND  NEW  ALCHEMY  269 

strangely  led  to  reoccupy  some  of  the  abandoned  strong- 
holds of  the  discredited  horde  of  alchemists.  We  can  see 
now  that  they  were  groping  toward  half-truths.  And 
their  instinct  in  selecting  lead  and  mercury  as  initial  forms 
of  matter  was  so  far  right  that  both  have  atomic  weights 
higher  than  those  of  gold  and  silver.  But  they  erred  hope- 
lessly in  pitting  their  feeble  artifices  against  the  imper- 
turbable stability,  measured  on  our  time  scale,  of  the 
created  world.  Irretrievable  disaster  and  delusion  could 
not  but  ensue  from  their  attempts  to  control  the  uncontrol- 
lable, and  to  exploit  inaccessible  treasure  stores.  We  know 
better.  Radio-activity  is  the  least  manageable  of  natural 
processes.  It  will  not  be  interfered  with.  We  can  only 
look  on  in  wonder  while  it  deploys  its  irresistible  unknown 
forces.  They  reveal  latent  possibilities  of  mechanical  power 
fabulous  in  amount,  and  within,  it  might  be  said,  a  hand's 
breadth  of  being  industrially  available;  yet  we  are  pre- 
cluded from  their  employment.1  Base  metals,  we  suspect 
with  reason,  are  continually  becoming  ennobled;  but  the 
gates  of  the  half -seen  Eldorado  remain  closed.  Will  they 
remain  closed  forever  ?  That  is  an  unread  enigma.  Should 
human  ingenuity  find  means,  in  the  future,  to  fling  them 
wide,  the  newer  alchemy  will  far  outbid  the  promises  of  the 
old,  and  will  cap  its  illusory  performances  with  as  yet 
unimaginable  realities.  Their  accomplishment,  however, 
will  consist  not  in  the  lavish  production  of  silver  and  gold, 
but  in  the  subjugation  of  the  untold  energy  accumulated 
at  the  beginning  of  the  world  in  complex  atomic  systems. 
Nature  here  sits  entrenched  in  her  last  fastness.  The  more 
sanguine  among  us  anticipate  its  reduction.  Others  be- 
lieve it  to  be  impregnable.  The  forces  that  hold  it  will  cer- 
tainly not  capitulate  soon  or  easily.  The  siege  must  be 
prolonged  and  difficult;  the  issue  is  doubtful. 

*See  Professor  Rutherford's  article  "Radium — the  Cause  of  the 
Earth's  Heat"  in  Harper's  Monthly  for  Feb.  1905, 


RADIOACTIVITY1 

BY  MADAME  MAEIE  CUKIE 

A  BRIEF  RESUME  OF  OUR  PRESENT  KNOWLEDGE 

THE  discovery  of  radioactivity  is  comparatively  recent, 
going  back  only  to  1896,  the  year  in  which  the  radiant 
properties  of  uranium  were  proved  by  Henri  Becquerel. 

The  development  of  the  science  since  has  been  extremely 
rapid,  and  among  the  numerous  results  obtained  are  some 
whose  general  scope  is  so  widely  extended  that  radioactivity 
constitutes  to-day  an  independent  and  important  branch  of 
the  physico-chemical  sciences  occupying  a  precisely  defined 
field  of  its  own. 

In  the  study  of  radioactivity  the  knowledge  of  the 
chemist  and  that  of  the  physicist  find  applications  of  equal 
importance. 

If  the  methods  of  analytic  chemistry  are  constantly  em- 
ployed for  the  extraction  of  radioactive  substances  from 
their  mineral  compounds,  various  methods  of  physical 
measurement,  and  in  particular,  of  electrometry,  are  of 
current  usage  for  the  study  of  these  substances. 

It  is  particularly  interesting  to  remark  the  close  connec- 
tion which  exists  between  the  rapid  development  of 
radioactivity  and  the  results  obtained  in  a  series  of  theo- 
retical and  experimental  researches  upon  the  nature  of 
electromagnetic  phenomena,  and  upon  the  passage  of  the 
electric  current  through  gases. 

These  researches,  which  have  established  with  great  pre- 
cision the  conception  of  the  corpuscular  structure  of 
electricity,  comprise  the  study  of  the  cathodic  and  positive 

1  Introduction  to  Madame  Curie's  Traite  de  Radio-active,  pub- 
lishers, Gauthier-Villars.  Translation  in  Scientific  American  Sup- 
plement, December,  1910,  used  by  permission  of  the  author. 

270 


RADIOACTIVITY  271 

rays,  the  discovery  and  study  of  Rontgen  rays,  and  the 
study  of  gaseous  ions.  They  have  led  to  the  idea  of  the 
existence  of  particles  which  carry  positive  or  negative 
charges,  and  which  may  have  dimensions  comparable  to 
atomic  dimensions,  or  possibly  dimensions  considerably 
smaller. 

The  theory  of  ionization,  which  has  been  established  to 
explain  the  characteristics  of  electric  conductivity  in  gases, 
has  been  recognized  as  likely  to  furnish  an  interpretation 
of  the  conductivity  acquired  by  a  gas  submitted  to  the 
action  of  a  radioactive  body ;  this  theory  has  been  applied 
to  the  study  of  radiations  emitted  by  radioactive  sub- 
stances, and  constitutes  from  this  point  of  view  a  very 
valuable  instrument  of  research. 

Moreover,  the  rays  of  radioactive  bodies  present  analogies 
to  cathodic,  positive,  and  Rontgen  rays,  and  can  often 
be  studied  by  analogous  methods. 

It  may  be  said  that  the  discovery  of  radioactivity 
occurred  at  a  time  when  the  ground  was  admirably  pre- 
pared. 

Closely  allied  to  physics  and  chemistry,  and  borrowing 
the  methods  of  work  of  these  two  sciences,  radioactivity 
brings  to  them  in  exchange,  elements  of  renewal. 

To  chemistry  it  gives  a  new  method  for  the  discovery, 
the  separation,  and  the  study  of  the  elements,  as  well  as  the 
knowledge  of  a  certain  number  of  new  elements  of  very 
curious  properties— first  of  all,  radium;  and  finally,  the 
idea— of  capital  importance— of  the  possibility  of  atomic 
transformations  under  conditions  subject  to  the  control  of 
experience. 

To  physics,  and  above  all,  to  modern  theories  of  cor- 
puscles, it  brings  a  world  of  new  phenomena  whose  study 
is  a  source  of  progress  for  these  theories.  One  might  cite, 
for  example,  the  emission  of  particles  carrying  electric 
charges  and  having  a  considerable  rapidity,  whose  motion 
does  not  obey  the  ordinary  laws  of  mechanics,  and  to  which 
one  may  apply,  with  the  purpose  of  verifying  and  develop- 


272  MODERN  SCIENCE  READER 

ing  them,  recent  theories  relative  to  electricity  and  to 
matter. 

But  though  radioactivity  is  in  close  relation  to  physics 
and  chemistry  above  all,  it  is  not  foreign  to  other  domains 
of  science,  and  in  these  acquires  increasing  importance. 

Radioactive  phenomena  are  so  varied,  their  manifesta- 
tions are  so  diverse  and  so  widespread  in  the  universe,  that 
they  should  be  taken  into  consideration  in  the  study  of  the 
natural  sciences,  especially  in  physiology  and  therapeutics, 
in  meteorology  and  geology. 

Many  laboratories  actually  devote  themselves  to  the  study 
of  radioactivity.  Institutes  are  being  created  for  the  cen- 
tralization of  relatively  important  quantities  of  radium, 
the  principal  instrument  of  research  in  this  new  domain. 
And  by  reason  of  these  efforts  the  importance  of  the  subject 
must  still  further  increase. 

I  published  in  1903  a  small  volume  entitled  Researches 
Upon  the  Radioactive  Substances,  in  which  was  reviewed 
the  state  of  the  subject  at  that  period.  In  1905  appeared 
the  excellent  treatise  of  Professor  Rutherford,  which  has 
had  a  more  complete  recent  edition  and  has  rendered  great 
service. 

In  the  present  work  I  have  tried  to  give  an  exposition  as 
complete  as  possible  of  the  phenomena  of  radioactivity,  in 
the  actual  state  of  our  present  knowledge. 

The  plan  of  my  first  book  has  been  preserved  in  part,  but 
the  work  comprises  a  much  more  ample  field,  corresponding 

to  the  sudden  development  of  the  science. 

******** 

Radioactivity  is  a  new  property  of  matter  which  has  been 
observed  in  certain  substances.  Nothing  warrants  us  in 
actually  affirming  that  this  is  a  general  property  of  matter, 
though  this  opinion  presents  nothing  a  priori  impossible, 
and  may  even  seem  quite  natural. 

Radioactive  bodies  are  sources  of  energy  whose  disen- 
gagement manifests  itself  by  diverse  effects:  the  emission 
of  radiations,  of  heat,  of  light,  of  electricity. 


RADIOACTIVITY  273 

This  disengagement  of  energy  is  essentially  connected 
with  the  atom  of  the  substance;  it  constitutes  an  atomic 
phenomenon ;  moreover,  it  is  spontaneous.  These  two  char- 
acteristics are  essential. 

We  have  actual  knowledge  of  bodies  feebly  radioactive: 
uranium  and  thorium ;  and  of  many  bodies  strongly  radio- 
active: radium,  polonium,  actinium,  radiothorium,  ionium. 

These  bodies  are  found  in  nature  in  an  extreme  state  of 
dilution ;  and  this  is  not  the  effect  of  chance. 

Among  the  strongly  radioactive  bodies,  radium  alone  has 
been  isolated  in  the  state  of  a  pure  salt ;  in  the  richest  min- 
erals this  body  is  found  in  the  proportion  of  a  few? 
decigrams  per  ton  of  mineral. 

Radioactive  substances  emit  rays  which  have  the  faculty 
of  impressing  sensitive  plates,  of  exciting  phosphorescence, 
and  of  rendering  gases  conductors  of  electricity ;  but  which 
do  not  exhibit  refraction,  polarization,  or  regular  reflection. 

These  rays  offer,  therefore,  analogies  to  cathodic,  positive, 
and  Rontgen  rays.  An  attentive  examination  has  proved 
that  the  ray-emission  of  radioactive  bodies  can  be  divided 
into  three  groups,  /?,  a,  y,  respectively  analogous  to  the 
three  groups  of  rays  which  have  just  been  named,  and 
which  are  formed  in  a  Crookes  tube. 

The  /?  rays  are  constituted  by  an  emission  of  negative 
electrons,  and  the  a  rays  by  an  emission  of  particles  posi- 
tively charged,  while  the  y  rays  are  not  charged.  The 
emission  of  the  rays  and  the  ft  rays  correspond  to  a  spon- 
taneous disengagement  of  electricity  by  the  radioactive 
bodies. 

The  rays  of  these  bodies  produce  numerous  effects  of  vari- 
ous nature:  chemical  effects,  of  which  the  most  important 
is  the  decomposition  of  water ;  physiological  effects,  such  as 
the  action  upon  the  epidermis  and  other  tissues— an  action 
which  is  currently  employed  for  medical  applications. 
Certain  radioactive  substances  are  spontaneously  luminous. 

The  radioactive  bodies  are  sources  of  heat.  Radium 
gives  rise  to  a  disengagement  of  heat  of  118  cal.  per  gram 
18 


274  MODERN  SCIENCE  READER 

per  hour,  and  that  without  the  state  of  the  substance  being 
appreciably  altered  during  many  years. 

This  extremely  remarkable  fact  establishes  a  fundamental 
distinction  between  radium  and  ordinary  elements,  and  is 
in  accord  with  the  actual  conception  which  attributes 
radioactivity  to  a  transformation  of  the  atom. 

The  radioactive  substances  may  possess  a  constant  activ- 
ity, at  least,  apparently,  within  the  limits  of  our  observa- 
tions: such  are  uranium,  thorium,  radium,  actinium.  In 
other  substances,  e.  g.,  in  polonium,  a  slow  diminution  of 
activity  in  the  lapse  of  time  has  been  observed. 

Lastly,  radioactive  phenomena  of  much  shorter  duration 
still,  have  been  observed. 

.  Thus,  radium,  thorium,  and  actinium  disengage  contin- 
uously radioactive  gases  called  emanations,  whose  activity 
in  time  disappears;  quite  slowly  in  the  case  of  radium, 
very  rapidly  in  the  case  of  thorium  and  actinium. 

These  emanations  themselves  produce  on  the  exposed 
surfaces  active  deposits  which  also  disappear  in  the  course 
of  a  few  hours  or  days.  This  is  the  phenomena  of  induced 
radioactivity. 

We  can,  also,  by  means  of  suitable  chemical  reactions, 
separate  from  uranium  or  thorium  radioactive  substances 
which  are  continuously  produced  by  these  bodies,  and  whose 
activity  disappears  progressively  in  a  few  months. 

All  these  phenomena  can  be  explained  satisfactorily  by 
admitting  the  production  and  destruction  of  radioactive 
matter  according  to  precisely  determined  laws. 

The  radioactive  properties  are  in  fact  very  varied;  the 
diverse  forms  of  ephemeral  radioactivity  are  distinguished 
from  each  other  by  the  nature  of  the  rays  emitted,  and  by 
the  rapidity  of  the  disappearance. 

It  may  be  admitted  that  the  production  or  the  destruction 
of  a  distinct  form  of  radioactivity  corresponds  to  the  pro- 
duction or  destruction  of  a  chemically  distinct  substance, 
and  since  radioactivity  is  an  atomic  phenomenon,  it  con- 
cerns the  production  and  destruction  of  atoms. 


RADIOACTIVITY  275 

This  view  constitutes  an  extension  of  ideas  upon  the 
atomic  nature  of  radioactivity,  ideas  which  have  led  to  the 
discovery  of  radium. 

The  theory  of  the  transformation  of  radioactive  elements 
which  has  been  developed  by  Rutherford  and  Soddy  is  now 
generally  adopted. 

According  to  this  theory  there  exist  no  invariable  radio- 
active substances,  but  each  of  them  undergoes  in  the  course 
of  time  a  more  or  less  rapid  progressive  destruction. 

A  chemically  simple  radioactive  substance  is  destroyed 
in  such  a  manner  that  the  rapidity  of  the  destruction  is 
proportional  to  the  quantity  present.  Consequently  this 
quantity  decreases  according  to  a  simple  exponential  law, 
characterized  by  an  invariable  coefficient,  which  depends 
on  the  nature  of  the  substance  and  may  serve  to  define  it. 

These  coefficients,  or  radioactive  constants,  seem  inde- 
pendent of  experimental  conditions  and  capable  of  consti- 
tuting standards  of  time. 

The  destruction  of  atoms  may  be  compared  to  an  explo- 
sion, at  which  time  fragments  of  the  atoms  may  be  thrown 
off  with  or  without  an  electric  charge. 

The  resulting  products  may  be  either  inactive  or  en- 
dowed with  radioactivity,  and  in  the  latter  case  the  newly 
formed  atom  is  not  itself  stable,  but  must  submit  to  a  new 
disintegration  at  the  end  of  a  longer  or  shorter  time. 

When  the  destruction  of  a  form  of  ephemeral  radio- 
activity occurs  according  to  a  complex  law,  this  law  can 
always  be  represented  by  an  algebraic  sum  of  exponential 
terms,  which  is  interpreted  as  a  succession  of  simple  trans- 
formations of  limited  number.  Experience  has  shown  that 
in  this  case  the  various  terms  of  the  series  may  be  considered 
as  representing  simple  radioactive  substances  of  which  cer- 
tain ones  are  capable  of  being  separated. 

In  pursuing  the  analysis  of  radioactive  phenomena,  we 
succeed  in  establishing,  starting  from  a  primary  substance, 
a  succession  of  terms  which  succeed  one  another  in  the 
series  of  radioactive  transformations. 


276  MODERN  SCIENCE  READER 

We  thus  obtain  families  of  elements  allied  by  a  relation- 
ship which  connects  them  in  a  common  but  distinct  origin. 
Such  are :  the  family  of  radium,  which  comprises  polonium 
also ;  the  family  of  uranium ;  of  thorium ;  of  actinium. 

Radium  itself  is  not  a  primary  substance,  but  probably 
derives  from  uranium.  We  are  confronted,  in  fact,  by  the 
existence  of  about  thirty  radioactive  elements,  of  which 
many,  in  truth,  will  never  be  characterized  as  such,  because 
they  have  too  brief  an  existence. 

In  fact  only  those  radioactive  elements  can  accumulate 
in  appreciable  quantities,  of  which  there  is  a  continuous 
production,  and  in  which  the  rapidity  of  destruction  of 
the  quantity  produced  is  not  too  great. 

On  the  other  hand,  the  intensity  of  radioactive  phe- 
nomena is  proportional  to  the  rapidity  of  destruction ;  and 
if  we  compare  bodies  of  analogous  ray-emission  and  in  sim- 
ilar quantities,  the  bodies  most  strongly  radioactive  are 
those  which  have  the  greatest  rapidity  of  destruction. 
Hence,  the  most  strongly  radioactive  substances  are  those 
which  we  should  expect  to  find  in  nature  in  smallest  pro- 
portions, and  this  is  borne  out  by  experience. 

Among  the  products  of  destruction  of  radioactive  bodies 
is  one  which  is  particularly  interesting:  the  gas  helium, 
which  is  produced  constantly  by  radium,  actinium,  polon- 
ium, uranium,  and  thorium. 

Experience  has  proved  that  the  atoms  of  helium  emitted 
should  be  considered  as  particles  which  have  lost  their 
electric  charge. 

On  the  other  hand,  the  a  rays  of  the  various  radioac- 
tive bodies  seem  constituted  of  the  same  material  particles. 

It  results  from  this  that  the  atom  of  helium  forms,  in  all 
probability,  one  of  the  constituents  of  all,  or  nearly  all, 
radioactive  atoms,  and  perhaps  a  constituent  of  atomic 
structures  in  general. 

The  discovery  of  the  production  of  helium  by  radium  is 
due  to  Ramsay  and  Soddy  and  constitutes  one  of  the  most 
important  facts  in  the  history  of  radioactivity. 


RADIOACTIVITY  277 

Certain  radioactive  transformations  are  very  slow ;  e.  g., 
the  destruction  of  uranium  and  of  thorium.  The  effects  of 
the  transformation  are  in  these  cases  very  insignificant 
even  after  many  years. 

But  in  the  radioactive  minerals  these  same  transforma- 
tions may  have  been  produced  during  the  process  of  time 
of  geologic  epochs,  and  hence  the  study  of  the  mineral  per- 
mits us  to  determine  the  relations  of  the  radioactive  bodies. 

Inversely,  if  one  such  relation  is  known  we  can  deduce 
from  it  the  length  of  time  during  which  the  transformation 
has  taken  place  in  an  unaltered  mineral.  Thus  by  the 
accumulation  of  helium  occluded  in  minerals  we  can  esti- 
mate the  age  of  the  latter. 

If  it  were  proved  that  all  matter  is  more  or  less  radio- 
active, the  relative  proportions  of  the  elements  in  the  min- 
erals could  be  studied  with  the  view  of  making  evident  the 
relations  of  genesis  among  the  elements.  To  terminate  this 
brief  review  of  the  domain  of  radioactivity  I  will  indicate 
how  great  is  the  disengagement  of  energy  by  radioactive 
bodies. 

Thus,  for  radium,  whose  rapidity  of  destruction  is 
approximately  known  (this  rapidity  is  such  that  the  radium 
is  half  gone  in  about  2,000  years),  the  destruction  of  a 
gram  of  matter  involves  the  disengagement  of  a  quantity 
of  heat  equal  to  that  which  results  from  the  combustion  of 
500  kilograms  of  carbon  or  70  kilograms  of  hydrogen. 

We  must  conclude  that  the  internal  energy  of  an  atom 
is  very  great  in  relation  to  that  which  is  brought  into  play 
at  the  time  of  the  combination  of  atoms  in  a  molecule.  This 
fact  is  probably  of  a  nature  to  explain  the  independence  of 
radioactive  phenomena  of  experimental  conditions. 

Among  the  attempts  which  have  been  made  to  influence 
these  phenomena,  none  has  yet  given  a  positive  result. 
Radioactivity  results  from  the  destruction  of  certain  atoms, 
and  this  destruction  appears  to  us  as  a  spontaneous 
phenomenon. 

Experience  shows  also  that  everything  takes  place  as  if 


278  MODERN  SCIENCE  READER 

the  probability  of  the  destruction  was,  at  the  same  instant, 
the  same  for  all  the  atoms  of  the  same  matter.  It  is  thus 
that  we  interpret  the  exponential  laws  of  the  destruction 
and  the  divergences  from  this  law. 

It  appears  inevitable  to  admit  that  the  destruction  of  an 
individual  atom  at  a  given  moment  results  from  particular 
circumstances  which  the  state  of  this  atom  and  the  influence 
of  exterior  agents  may  cause  to  intervene. 

Thus  the  determining  cause  of  radioactive  phenomena 
remains  still  unknown. 

In  this  book  the  exposition  of  the  phenomena  of  radio- 
activity properly  so  called  has  been  preceded  by  an  expo- 
sition of  the  theory  of  gaseous  ions,  and  by  a  resume  of  the 
most  important  knowledge  concerning  cathodic,  positive, 
and  Rontgen  rays,  and  of  the  properties  of  electrified 
particles  in  motion.  This  knowledge  is  indispensable  to 
the  study  of  the  subject  in  hand.  A  later  chapter  has  been 
devoted  to  the  description  of  methods  of  measurement. 

After  the  detailed  description  of  the  discovery  and  prep- 
aration of  radioactive  substances  comes  the  study  of  radio- 
active emanations  and  of  induced  radioactivity,  and  of 
radiations  emitted  by  radioactive  bodies. 

The  radioactive  substances  are  afterward  classified  by 
families,  with  the  study  for  each  of  them  of  the  ensemble 
of  properties  and  of  the  nature  of  radioactive  transforma- 
tions. 


VISIBLE  MOLECULES,  CORPUSCLES 
AND  IONS1 

WHEN,  a  hundred  years  ago,  John  Dalton  gave  its  modern 
shape  to  the  atomic  theory,  which  may  be  traced  back  to 
ancient  philosophy  and  to  Democritus,  nobody  expected  that 
scientists  would  some  day  isolate,  or  at  least  render  visible, 
the  single  atom  and  molecule.  The  kinetic  theory  of  gases 
ascribed  the  gas  pressure  to  the  bombardment  of  the  walls 
of  the  confining  envelope  by  the  gas  molecules.  It  taught 
us  how  to  count  and  to  measure  the  molecules.  But  it  did 
not  bring  the  probability  of  our  ever  seeing  them  any 
nearer ;  that  looked  hopeless  with  3  X  1019  molecules  in  a 
cubic  centimeter  of  a  gas,  and  640  trillion  of  atoms  in 
a  milligram  of  hydrogen.  The  recent  discovery  of  par- 
ticles one-seventeen  hundredth  of  the  size  of  a  hydrogen 
atom  offers  problems  even  more  difficult  than  those  of  an 
atom.  Yet  it  is  claimed  that  the  visibility  of  the  smallest 
particles  has  been  demonstrated  in  various  ways.  It  may 
be  opportune  to  examine  some  of  the  experiments  on  which 
such  claims  are  based. 

The  existence  of  particles  smaller  than  the  atom  would 
not  in  reality  contradict  the  atomic  theory.  The  atomic 
theory  does  not  assert  that  the  atom  is  the  smallest  particle 
capable  of  existence.  The  name  ''atom/'  indeed,  suggests 
something  that  cannot  further  be  cut  or  divided.  But  the 
essence  of  the  theory  is  that  an  elementary  substance  con- 
sists of  particles  or  atoms  peculiar  to  that  element,  and  that 
the  single  atom  is  the  smallest  particle  which  can  enter  into 
combination.  The  molecule  is  the  combination  product  of 
atoms.  The  atom  need  not  necessarily  be  the  smallest  ulti- 
mate particle,  and  many  considerations  induce  modern 
^Engineering,  April  8,  1910. 
279 


280  MODERN  SCIENCE  READER 

science  to  believe  that  the  atom  may  itself  have  a  constitu- 
tion. The  atoms  of  different  elements  differ  from  one 
another.  Yet  the  modern  scientist  feels  with  the  ancient 
philosopher  that  there  may,  after  all,  be  only  one  kind  of 
matter,  which,  being  grouped  in  different  ways,  gives  rise 
to  different  elements  and  bodies.  There  are  certainly  dif- 
ficulties in  the  suggestion  that  atoms  or  molecules  should 
be  able  to  split  off  corpuscles,  and  remain  substantially  what 
they  were,  while,  on  the  other  hand,  radium— probably  an 
elementary  metal— is  able  to  emit  radiations  which  turn 
into  helium— undoubtedly  a  gas.  But  those  researches  are 
not  completed  yet,  and  meanwhile  chemists  continue  to 
adhere  to  the  atomic  theory  which  has  proved  so  fruitful, 
and  to  determine  atomic  weights  with  the  greatest  possible 
care. 

The  demonstrations  of  the  possible  visibility  of  molecules 
are  based  on  observations  partly  made  in  less  controversial 
fields.  Colloids  have  furnished  the  first  suggestion  of 
visible  molecules  or  groups  of  molecules.  When  mud  is 
stirred  up,  the  particles  settle  quickly  again,  and  the  turbid 
liquid  can,  by  filtering,  be  cleared  of  suspended  particles. 
The  particles  of  an  oil  emulsion  take  a  long  time  to  settle, 
and  run  turbid  through  the  filter.  When  still  finer  par- 
ticles are  prepared,  for  instance,  by  volatilizing  metal  elec- 
trodes immersed  in  liquids,  the  cloudy  particles  will  not 
settle  for  many  days  or  months,  and  finally  it  may  be  im- 
possible to  decide  whether  an  emulsion  or  a  real  solution 
has  resulted.  It  is  quite  conceivable  that  the  transition 
from  a  suspension  to  a  solution  is  too  gradual  to  permit  of 
a  distinct  line  of  demarkation  being  drawn,  just  as  the 
three  states  of  aggregation  cannot  rigorously  be  distin- 
guished. Very  small  suspended  particles  now  are  in  con- 
stant oscillatory  movement.  These  movements  were  first 
observed  by  the  botanist  Brown  in  1827,  and  are  known  as 
Brownian  movements.  The  coarser  the  particles,  the 
slower  and  more  irregular  the  movements.  For  a  long 
time  they  were  ascribed  to  inequalities  of  temperature  in 


MOLECULES,  CORPUSCLES  AND  IONS   281 

the  turbid  liquid.  When  the  ultra-microscope  was  brought 
out  in  Jena,  the  study  of  this  curiosity  assumed  a  direct 
scientific  interest,  and  the  impression  gained  ground  that 
the  observer  really  watched  molecular  movements  akin  to 
those  which  the  particles  of  gases  describe  according  to  the 
kinetic  theory  of  gases.  The  idea  originated,  we  believe, 
with  Einstein ;  he  certainly  worked  out  the  mathematics  of 
the  problem.  During  the  past  few  years  J.  Perrin,  Gouy, 
Svedberg,  and  others  have  supplied  apparent  experimental 
proofs  for  the  molecular  character  of  the  movements. 
Perrin  counted  the  number  of  gamboge  granules  or  parti- 
cles, in  a  portion  of  his  colloidal  solution,  measured  their 
diameters,  masses,  and  paths,  and  calculated  their  average 
kinetic  energy.  He  concluded  that  the  granules  had  the 
same  average  energy  of  movement  as  the  molecules  of  the 
liquid  in  which  they  were  suspended,  and  that  they  behaved 
thus  like  molecules  of  a  very  high  molecular  weight. 

Now  molecules  of  a  high  molecular  weight— in  other 
words,  molecules  consisting  of  a  great  number  of  atoms  of 
different  elements— are  nothing  strange  to  the  chemist. 
Emil  Fischer,  in  his  famous  researches  on  the  albuminoids, 
has  come  to  very  high  molecular  weights  indeed.  In  his 
four  series  of  experiments  Perrin  dealt  with  granules 
whose  masses  varied  as  1  :  3  : 8  : 27.  Allowing  for  the 
coarseness  of  his  granules  and  the  friction  in  his  medium 
(water),  Perrin  deduced  for  the  number  N  of  molecules 
per  cubic  centimeter  very  nearly  the  same  figure,  3  X  1019, 
to  which  other  researches  have  led  us.  Estimates  of  this 
N,  we  should  add,  have  been  made  by  the  most  varied  and 
entirely  independent  methods.  Some  of  the  methods  give 
results  which,  it  may  be  foreseen,  should  be  considered  as 
upper  limits,  others  will  yield  lower  limits.  The  average 
accepted  value  for  N  was,  a  few  years  ago,  probably 
6  X  1019 ;  at  present  scientists  incline  to  half  that  value, 
3  X  1019. 

The  experiments  of  Ehrenhaft  confirm  those  of  Perrin. 
Ehrenhaft  volatilized  silver  electrodes  in  air;  the  fine-dust 


282  MODERN  SCIENCE  READER 

granules  thus  produced  exhibited  the  looked-for  Brownian 
movements,  and  the  free  path  was  longer  in  air  than  it  had 
been  for  granules  of  the  same  size  in  water.  Perrin's  cal- 
culations have,  on  the  other  hand,  been  questioned  by 
Duclaux.  But  we  appear  to  be  justified  in  assuming  that 
the  observer,  watching  the  movements  of  colloidal  particles, 
sees  movements  similar  to  those  which  we  ascribe  to  the 
invisible  molecules  of  gases. 

Another  demonstration  of  luminous  effects,  ascribed  to 
single  particles,  was  given  by  Crookes  in  London  and 
Regener  in  Berlin,  seven  or  eight  years  ago,  and  thus  be- 
fore the  above-mentioned  experiments  on  colloids  in  which 
molecules  are  supposed  to  be  concerned.  When  the  a  rays 
of  radium  are  allowed  to  fall  on  a  screen  or  fluorescent  zinc 
sulphide,  each  particle  seems  to  produce  a  flash  of  light 
like  a  tiny  spark,  and  brilliant  scintillations  are  observed. 
Still  more  instructive  is  the  demonstration  of  single  a 
particles,  which  Rutherford  and  Geiger  gave  in  the  Royal 
Institution  two  years  ago.  A  tube  containing  radium 
bromide  was  held  in  front  of  the  window  of  a  long  tube, 
several  feet  away  from  the  window,  so  that  only  a  few  a 
particles— perhaps  not  more  than  one  per  second— would 
find  their  way  to  the  electrometer  at  the  far  end  of  the 
tube.  A  sudden  jerk  of  the  electrometer  indicated  that  a 
particle  had  struck  and  the  number  of  particles  shot  out 
per  second  were  actually  counted  by  counting  the  jerks. 
Each  a  particle  is  supposed  to  represent  a  charged  atom  of 
helium,  which  turns  into  helium  gas  on  losing  its  electric 
charge.  Dewar  has  carefully  determined  how  much  helium 
is  produced  by  a  given  weight  of  radium  per  second,  and 
by  putting  that  figure  together  with  his  count  of  the  number 
of  a  particles  discharged  per  second,  Rutherford  arrived 
at  the  conclusion  that  1  cubic  centimeter  of  helium  is 
formed  by  2.56  X  1019  particles— a  most  remarkable  con- 
firmation of  the  N. 

Another  exemplification  of  the  visibility  of  molecules  or, 
at  any  rate,  of  the  discontinuity  of  an  apparently  homogen- 


MOLECULES,  CORPUSCLES  AND  IONS   283 

ous  solution,  is  due  to  the  late  Lobry  de  Bruyn,  and  has 
recently  been  verified  by  A.  Coehn.  It  refers  to  the  so- 
called  Tyndall  effect.  A  ray  of  light  is,  as  such,  invisible 
in  an  optically  empty  medium.  Passed  through  a  glass 
trough  the  beam  of  the  lantern  is  hardly  visible,  until  some 
turbid  medium  like  smoke  is  introduced  into  the  trough. 
The  light  cone  of  a  lens,  concentrated  into  pure  water, 
leaves  the  water  dark,  when  it  is  free  of  suspended  particles, 
dust,  etc.  It  is,  of  course,  exceedingly  difficult  to  free  the 
water  of  all  dust  and  floating  impurities.  Working  with 
the  greatest  care  Lobry  de  Bruyn  succeeded  in  obtaining 
pure  water,  in  which  the  light  cone  was  hardly  discern- 
ible. But  when  he  dissolved  cane  sugar  in  this  water, 
a  luminosity  was  noticed.  Coehn  has  repeated  this  experi- 
ment with  the  ultramicroscope  of  Zsigmondy,  and  the  light 
cone  then  observed  was  quite  uniform;  dust  particles  or 
colloids  would  have  shown  as  bright  points.  It  would, 
therefore,  appear  that  the  large  molecules  of  cane  sugar, 
dispersed  through  the  water,  make  the  water  sufficiently 
discontinuous  to  reflect  the  light. 

The  further  endeavors  of  Coehn  to  exemplify  this  dis- 
continuity in  solutions  in  which  a  transport  of  the  ions 
and  of  non-electrolytic  particles,  drifting  with  the  ions,  is 
produced  by  electrolysis,  will  be  better  understood  by  a 
description  of  some  very  remarkable  experiments  of  Kos- 
sonogow,  of  Kjew.  Kossonogow  studies  electrolysis  with 
the  aid  of  the  ultra-microscope.  He  bends  both  the  elec- 
trodes of  his  cells  twice  at  right  angles,  so  as  to  leave  a 
channel,  generally  0.2  millimeter  in  width,  between  the 
active  surfaces,  and  coats  the  other  portions  of  the  elec- 
trodes with  paraffin;  the  light  beam  is  sent  across  this 
channel  in  which  electrolysis  takes  place.  On  dissolving 
various  salts,  silver  nitrate,  copper  sulphate,  ammonium 
chloride,  and  others  in  water,  he  observed  at  once— before 
turning  on  the  current— some  luminosity  and  bright  specks 
in  Brown i an  movements.  Some  of  the  specks  were  no  doubt 
dust  particles.  But  the  just-mentioned  discontinuity  phe- 


284  MODERN  SCIENCE  READER 

nomena,  and  further  migration  of  the  ions,  were  also  con- 
cerned. For  the  luminosity  increased  when  the  current 
(of  10  volts,  e.  g.)  was  turned  on,  and  the  particles  were 
distinctly  seen  to  wander,  mostly  toward  the  cathode.  If 
dust  granules  had  alone  been  at  work,  the  current  should 
gradually  have  cleared  the  solution  of  such  granules.  But 
the  directed  movements  were  only  observed  when  there  was 
real  electrolysis,  and  no  movements  and  hardly  any  lumin- 
osity were  seen  when  the  solvent  was  not  water,  but  a  non- 
electrolyte,  like  benzol.  The  bright  specks  were,  moreover, 
deflected  from  their  rectilinear  paths  when  the  cell  was 
placed  in  a  strong  magnetic  field.  On  reversing  the  cur- 
rent, the  bright  specks  also  reversed  their  movements,  which 
took  place  at  the  rate  of  migrating  ions,  and  on  applying 
alternating  currents  the  particles  seemed  to  be  undecided 
which  way  to  move. 

All  these  observations  appear  to  indicate  that  the  mov- 
ing particles  are  either  ions,  or  other  bodies  or  molecules, 
drifting  together  with  the  ions,  and  it  has  long  ago  been 
pointed  out  that  the  migrating  ion  would  carry  some  of 
the  solvent  with  it.  The  following  observations  of  Kos- 
sonogow  are  of  particular  interest.  When  a  certain  critical 
potential  was  applied,  the  number  of  bright  specks  suddenly 
increased  very  much,  and  they  crowded  near  the  cathode, 
but  a  dark  space,  from  0.05  to  0.08  millimeter  in  width,  was 
always  left  close  to  the  cathode.  This  dark  cathode  space 
—so  well  known  from  experiments  on  the  electric  discharge 
through  gases— was  very  well  defined,  and  it  was  partic- 
ularly striking  when  cathodes  were  used  which  were  not 
plain,  but  curved  in  fanciful  ways.  The  boundary  of  the 
dark  space  always  kept  parallel  to  the  contours  of  the 
cathode.  Beyond  the  dark  space  the  bright  particles  were 
in  lively  motion;  but  no  bright  particles  crossed  the  dark 
space,  though  the  ions  must  traverse  it  to  be  deposited  on 
the  cathode.  It  looked,  Kossonogow  says,  as  if  the  ions  lost 
their  luminosity,  together  with  their  electric  charge,  when 
passing  the  dark  space.  When  the  critical  potential — 1 


MOLECULES,  CORPUSCLES  AND  IONS   285 

volt  for  silver  nitrate  in  water — was  exceeded,  another 
crowding  of  the  bright  spots  to  a  bright  band  was  noticed 
intermediate  between  the  electrodes.  The  crowding  of  the 
bright  points  and  the  dark  space  were  also  seen  in  copper 
sulphate.  When  silver  electrodes  were  dipped  into  a  col- 
loidal solution  of  silver  in  water,  the  phenomenon  changed. 
The  bright  spots  crowded  near  the  anode,  not  near  the 
cathode,  but  there  was  no  dark  space  separating  them  from 
the  anode. 

Whatever  one  may  think  of  the  interpretation  of  these 
phenomena,  it  will  be  conceded  that  the  decomposition 
products  of  electrolysis  are  concerned  in  them.  Whether 
the  bright  spots  seen  are  really  the  ions,  whether  the  optical 
discontinuity  is  really  due  to  single  molecules,  whether  the 
scintillations  and  electrometer  discharges  are  indeed  pro- 
duced by  single  a  rays— i.  e.,  single  charged  helium  atoms— 
and  whether  the  colloidal  granules  represent  real  analogues 
of  molecules,  whether,  in  brief,  the  phenomena,  which  we 
have  reviewed,  really  constitute  effects  of  ultimate  particles 
—these  questions  remain  open,  of  course.  Chemists  may 
at  times  decline  to  follow  physicists  into  some  of  their  novel 
theories.  But  problems  present  themselves  which  were 
unknown  to  the  exact  science  of  past  generations,  though 
such  questions  entered  into  their  speculations,  and  the  per- 
fection, especially  of  electrical  and  optical  methods  and 
instruments,  of  research  certainly  has  provided  us  with 
means  of  conducting  investigations  which  the  past  gener- 
ations could  hardly  have  hoped  to  attain. 


THE  ELECTRONIC  THEORY  OF 
MATTER1 

BY  SIR  OLIVEE  LODGE,  D.  So.,  F.  E.  S. 

IN  a  recent  number  of  Harper's  Magazine  Sir  Oliver 
Lodge  presents  a  popular  account  of  the  electronic  theory, 
which  is  well  worth  quoting : 

Our  present  view  of  an  atom  of  matter  is  something 
like  the  following:  Picture  to  one's  self  an  individualized 
mass  of  positive  electricity,  diffused  uniformly  over  a 
space  as  big  as  an  atom — say  a  sphere  of  which  200,000,000 
could  lie  edge  to  edge  in  an  inch,  or  such  that  a  million 
million  million  million  could  be  crowded  tightly  together 
into  an  apothecary's  grain.  Then  imagine  disseminated 
throughout  this  small  spherical  region  a  number  of  minute 
specks  of  negative  electricity,  all  exactly  alike,  and  all 
flying  about,  vigorously,  each  of  them  repelling  every 
other,  but  all  attracted  and  kept  in  their  orbits  by  the 
mass  of  positive  electricity  in  which  they  are  embedded 
and  flying  about.  In  so  far  as  an  atom  is  impenetrable  to 
other  atoms,  its  parts  act  on  the  sentinel  principle,  not  on 
the  crowd  principle. 

There  are  two  ways  of  keeping  hostile  people  out  of  an 
open  building;  one  is  to  fill  it  with  your  own  supporters, 
another  is  to  place  an  armed  policeman  at  every  door.  The 
electrons  are  extremely  energetic  and  forcible,  though  in 
bulk  mere  specks  or  centers  of  force.  Every  speck  is 
exactly  like  every  other,  and  each  is  of  the  size  and  weight 
appropriate  to  the  electron.  Different  atoms,  that  is,  atoms 
of  different  kinds  of  matter,  are  all  believed  to  be  composed 
in  the  same  sort  of  way;  but  if  the  atoms  of  a  substance 

Review  of  an  article  in  Harper's  Magazine,  from  Scientific  Ameri- 
can Supplement,  September  17,  1904. 

286 


ELECTRONIC  THEORY  OF  MATTER          287 

are  such  that  each  possesses  twenty-three  times  as  many 
electrons  as  hydrogen  has,  we  call  it  sodium.  If  each  atom 
has  two  hundred  times  as  many  as  hydrogen,  we  call  it  lead 
or  quicksilver.  If  it  has  still  more  than  that,  it  begins  to 
be  conspicuously  radioactive. 

It  would  seem  as  if  the  excessive  radiation  which  follows 
upon  an  overcrowded  condition  were  caused  by  the  prob- 
ability of  collision  or  encounter  between  the  parts  of  an 
atom;  just  as  every  now  and  then  among  the  stars  in  the 
sky  two  bodies  encounter  each  other,  and  a  great  blaze  of 
radiation,  or  temporary  star,  results.  Even  in  atoms  of 
which  the  parts  are  sparsely  distributed  such  occurrences 
are  not  impossible,  though  they  are  less  frequent,  and 
accordingly  it  is  to  be  expected  that  every  kind  of  matter 
may  be  radioactive  to  a  very  small  extent ;  a  probability 
which  is  now  justified  for  most  metals,  by  direct  experiment 
with  very  sensitive  means  of  detection. 

Indeed,  so  far  as  radiation  necessarily  accompanies  any 
change  of  motion  of  an  electron,  and  in  so  far  as  in  every 
atom  some  electrons  are  describing  orbits  and  are  therefore 
subject  to  centripetal  acceleration,  a  certain  amount  of 
atomic  radiation  is  inevitable,  on  the  electric  theory  of 
matter.  In  most  cases  it  is  imperceptibly  small,  but  it  must 
be  there,  and  accordingly  an  atom  must  be  slowly  under- 
mining its  own  constitution  by  the  gradual  emission  of  its 
internal  or  intrinsic  energy  in  the  form  of  ether-waves. 

Thus,  then,  it  is  reasonable  to  expect  that,  every  now  and 
then,  an  atom  will  break  up  or  collapse  or  divide  into  parts. 
This  process  has  been  observed  by  Rutherford,  of  Montreal. 
The  radiation  from  many  of  the  radioactive  substances,  on 
being  analyzed  by  a  magnet,  is  found  to  be  separable  into 
three  parts :  1,  the  so-called  ft  rays,  which  are  the  shot-off 
electrons  already  mentioned ;  2,  some  y  rays,  which  appear 
to  represent  an  ethereal  pulse — an  analogue  as  it  were  of 
the  sound-wave  caused  by  the  explosion  or  act  of  firing ;  and 
3,  more  important  than  either,  a  third  kind  of  projectile 
called  the  a  rays,  which  are  newly-formed  atoms  of  foreign 


288  MODERN  SCIENCE  READER 

matter  or  new  substance.  These  are  pitched  away  with 
extraordinary  violence  as  the  atom  breaks  up ;  they  produce 
by  their  bombardment  of  zinc  sulphide  the  bright  little 
flashes  seen  in  Crookes'  spinthariscope,  and  they  likewise 
generate  heat  when  they  are  stopped  by  any  obstacle.  They 
thus  keep  the  vessel  in  which  they  are  inclosed  at  a  tempera- 
ture a  degree  or  two  above  surrounding  bodies,  at  least  in 
the  case  of  the  most  active  known  substances,  radium  and 
its  emanation.  For  radium  converts  its  own  intra-atomic 
energy  into  heat  at  so  surprising  a  rate  that  it  could,  if  all 
of  the  heat  were  economized  and  none  allowed  to  escape, 
raise  its  own  weight  of  water  from  ordinary  temperature 
to  the  boiling-point  every  hour. 

The  number  of  atoms  breaking  up  in  any  perceptible 
portion  of  radium  salt  must  be  reckoned  in  millions  per 
second;  nevertheless,  the  proportion  of  atoms  which  are 
thus  undergoing  transformation  at  any  one  time  is  ex- 
tremely small.  If  they  could  be  seen  individually  most  of 
them  would  appear  quiescent  and  stable.  Of  every  ten 
thousand  atoms,  if  a  single  one  breaks  up  and  flings  away 
a  portion  of  itself  once  a  year,  that  would  be  enough  to 
account  for  all  the  activity  observed,  even  in  the  case  of 
so  exceptionally  active  a  substance  as  radium;  hence  the 
apparent  stability  of  ordinary  matter  is  not  surprising. 

The  thus  projected  atomic  fragments  were  measured  by 
Rutherford,  who  found  them  deflected  by  a  magnet  in  the 
opposite  direction  to  the  electron  projectiles,  and  were 
therefore  proved  to  be  positively  charged;  but  they  are 
deflected  so  slightly  that  they  must  be  very  massive  bodies, 
1,600  times  as  massive  as  an  electron,  or  twice  the  weight 
of  hydrogen.  A  substance  with  this  atomic  wreight  is 
known,  viz.,  helium:  and  surely  enough  the  discoverer  of 
helium,  Sir  W.  Ramsay,  working  with  Mr.  Soddy,  a  recent 
colleague  of  Rutherford,  has  witnessed  the  helium  spectrum 
gradually  develop  in  a  tube  into  which  nothing  but  radium 
emanation  had  been  put. 

Matter,  then,  appears  to  be   composed  of  positive  and 


ELECTRONIC  THEORY  OF  MATTER          289 

negative  electricity  and  nothing  else.  All  its  newly-dis- 
covered, as  well  as  all  its  long-known,  properties  can  thus 
be  explained— even  the  long-standing  puzzle  of  "cohesion" 
shows  signs  of  giving  way.  The  only  outstanding  still  in- 
tractable physical  property  is  "gravitation,"  and  no  satis- 
factory theory  of  the  nature  of  gravitation  has  been  so  far 
forthcoming.  I  doubt,  however,  if  it  is  far  away.  It 
would  seem  to  be  a  slight  but  quite  uniform  secondary  or 
residual  effect  due  to  the  immersion  of  a  negative  electron 
in  a  positive  atmosphere.  It  is  a  mutual  force  between  one 
atomic  system  and  another,  which  is  proportional  to  the 
number  of  electrons  in  each.  It  is  quite  doubtful  whether 
it  is  displayed  by  an  isolated,  or  disembodied  electron,  but 
the  act  of  immersing  an  electron  in  its  attracting  atmos- 
phere may  develop  it.  We  know  too  little  about  electricity, 
especially  about  positive  electricity,  to  be  able  to  justify  or 
expand  such  a  guess ;  but,  as  a  guess  and  no  more,  I  venture 
to  throw  it  out ;  believing  it  to  be  a  static  residual  strain 
effect,  inherent  in  the  constitution  of  each  atom. 


19 


THE  ETHER  OF  SPACE1 

BY  SIE  OLIVER  LODGE,  D.  Sc.,  F.  R.  S. 

THIRTY  years  ago  Clerk  Maxwell  gave  a  remarkable  lec- 
ture on  "Action  at  a  Distance."  Like  most  other  natural 
philosophers,  he  held  that  action  at  a  distance  across  empty 
space  is  impossible ;  in  other  words,  that  matter  cannot  act 
where  it  is  not,  but  only  where  it  is.  The  question  * '  Where 
is  it?"  is  a  further  question  that  may  demand  attention 
and  require  more  than  a  superficial  answer.  For  it  can  be 
argued  on  the  hydrodynamic  or  vortex  theory  of  matter, 
as  well  as  on  the  electrical  theory,  that  every  atom  of 
matter  has  a  universal,  though  nearly  infinitesimal,  prev- 
alence, and  extends  everywhere,  since  there  is  no  definite 
sharp  boundary  or  limiting  periphery  to  the  region  dis- 
turbed by  its  existence.  The  lines  of  force  of  an  isolated 
electric  charge  extend  throughout  illimitable  space.  And 
though  a  charge  of  opposite  sign  will  curve  and  concen- 
trate them,  yet  it  is  possible  to  deal  with  both  charges,  by 
the  method  of  superposition,  as  if  they  each  existed  sepa- 
rately without  the  other.  In  that  case,  therefore,  however 
far  they  reach,  such  nuclei  clearly  exert  no  "action  at  a 
distance"  in  the  technical  sense. 

Some  philosophers  have  reason  to  suppose  that  mind  can 
act  directly  on  mind  without  intervening  mechanism,  and 
sometimes  that  has  been  spoken  of  as  genuine  action  at 
a  distance ;  but,  in  the  first  place,  no  proper  conception 
or  physical  model  can  be  made  of  such  a  process,  nor  is  it 
clear  that  space  and  distance  have  any  particular  mean- 
ing in  the  region  of  psychology.  The  links  between  mind 

*A  Friday  evening  discourse  at  the  Royal  Institution  of  Great 
Britain  on  the  21st  of  February,  1908. 

Published  in  the  North  American  Review  for  May,  1908. 

290 


THE  ETHER  OF  SPACE  291 

and  mind  may  be  something  quite  other  than  physical 
proximity,  and  in  denying  action  at  a  distance  across  empty 
space  I  am  not  denying  telepathy  or  other  activities  of  a 
non-physical  kind;  for  although  brain  disturbance  is  cer- 
tainly physical,  and  is  an  essential  concomitant  of  mental 
action,  whether  of  the  sending  or  receiving  variety,  yet  we 
know  from  the  case  of  heat  that  a  material  movement  can 
be  excited  in  one  place  at  the  expense  of  corresponding 
movement  in  another,  without  any  similar  kind  of  trans- 
mission or  material  connection  between  the  two  places:  the 
thing  that  travels  across  vacuum  is  not  heat. 

In  all  cases  where  physical  motion  is  involved,  however, 
I  would  have  a  medium  sought  for;  it  may  not  be  matter, 
but  it  must  be  something;  there  must  be  a  connecting  link 
of  some  kind,  or  the  transference  cannot  occur.  There  can 
be  no  attraction  across  really  empty  space.  And  even 
when  a  material  link  exists,  so  that  the  connection  appears 
obvious,  the  explanation  is  not  complete;  for  when  the 
mechanism  of  attraction  is  understood,  it  will  be  found 
that  a  body  really  only  moves  because  it  is  pushed  by 
something  from  behind.  The  essential  force  in  nature  is 
the  vis  a  tergo.  So  when  we  have  found  the  " traces"  or 
discovered  the  connecting  thread,  we  still  run  up  against 
the  word  "cohesion,"  and  ought  to  be  exercised  in  our 
minds  as  to  its  ultimate  meaning.  Why  the  particles  of  a 
rod  should  follow,  when  one  end  is  pulled,  is  a  matter  re- 
quiring explanation ;  and  the  only  explanation  that  can  be 
given  involves,  in  some  form  or  other,  a  continuous  medium 
connecting  the  discrete  and  separated  particles  or  atoms  of 
matter. 

When  a  steel  spring  is  bent  or  distorted,  what  is  it  that  is 
really  strained?  Not  the  atoms— the  atoms  are  only  dis- 
placed; it  is  the  connecting  links  that  are  strained— the 
connecting  medium— the  ether.  Distortion  of  a  spring  is 
really  distortion  of  the  ether.  All  strain  exists  in  the 
ether.  Matter  can  only  be  moved.  Contact  does  not  exist 
between  the  atoms  of  matter  as  we  know  them ;  it  is  doubt- 


292  MODERN  SCIENCE  READER 

ful  if  a  piece  of  matter  ever  touches  another  piece,  any 
more  than  a  comet  touches  the  sun  when  it  appears  to 
rebound  from  it ;  but  the  atoms  are  connected,  as  the  plan- 
ets, the  comets  and  the  sun  are  connected,  by  a  continuous 
plenum  without  break  or  discontinuity  of  any  kind.  Mat- 
ter acts  on  matter  solely  through  the  ether.  But  whether 
matter  is  a  thing  utterly  distinct  and  separate  from  the 
ether,  or  whether  it  is  a  specifically  modified  portion  of  it 
— modified  in  such  a  way  as  to  be  susceptible  of  locomotion, 
and  yet  continuous  with  all  the  rest  of  the  ether— which 
can  be  said  to  extend  everywhere,  far  beyond  the  bounds  of 
the  modified  and  tangible  portion  called  matter— are  ques- 
tions demanding,  and  I  may  say  in  process  of  receiving, 
answers. 

Every  such  answer  involves  some  view  of  the  universal, 
and  possibly  infinite,  uniform  omnipresent  connecting 
medium,  the  ether  of  space. 

Let  us  now  recall  the  chief  lines  of  evidence  on  which 
the  existence  of  such  a  medium  is  believed  in,  and  our 
knowledge  of  it  is  based.  First  of  all,  Newton  recognized 
the  need  of  a  medium  for  explaining  gravitation.  In  his 
"Optical  Queries,"  he  shows  that  if  the  pressure  of  this 
medium  is  less  in  the  neighborhood  of  material  bodies  than 
at  great  distances  from  them,  those  bodies  will  be  driven 
toward  each  other;  and  that  if  the  diminution  of  pressure 
is  inversely  as  the  distance  from  the  dense  body,  the  law 
will  be  that  of  gravitation. 

All  that  is  required,  therefore,  to  explain  gravity  is  a 
diminution  of  pressure,  or  increase  of  tension,  caused  by 
the  formation  of  a  matter  unit— that  is  to  say,  of  an  electron 
or  corpuscle;  and  although  we  do  not  yet  know  what  an 
electron  is — whether  it  be  a  strain  center,  or  what  kind  of 
singularity  it  is  in  the  ether— there  is  no  difficulty  in  sup- 
posing that  a  slight,  almost  infinitesimal,  strain  or  afc 
tempted  rarefaction  should  have  been  produced  in  the 
ether  whenever  an  electron  came  into  being;  to  be  relaxed 
again  only  on  its  resolution  and  destruction.  Strictly 


THE  ETHER  OF  SPACE  293 

speaking,  it  is  not  a  real  strain,  but  only  a  "stress"  since 
there  can  be  no  actual  yield,  but  only  a  pull  or  tension, 
extending  in  all  directions  toward  infinity. 

The  tension  required  per  unit  of  matter  is  almost  ludi- 
crously small,  and  yet  in  the  aggregate,  near  such  a  body 
as  a  planet,  it  becomes  enormous. 

The  force  with  which  the  moon  is  held  in  its  orbit  would 
be  great  enough  to  tear  asunder  a  steel  rod  four  hundred 
miles  thick,  with  a  tenacity  of  30  tons  per  square  inch ;  so 
that  if  the  moon  and  earth  were  connected  by  steel  instead 
of  by  gravity,  a  forest  of  pillars  would  be  necessary  to 
whirl  the  system  once  a  month  round  their  common  center 
of  gravity.  Such  a  force  necessarily  implies  enormous 
tension  or  pressure  in  the  medium.  Maxwell  calculates 
that  the  gravitational  stress  near  the  earth,  which  we  must 
suppose  to  exist  in  the  invisible  medium,  is  3,000  times 
greater  than  what  the  strongest  steel  could  stand ;  and  near 
the  sun  it  should  be  2,500  times  as  great  as  that. 

The  question  has  arisen  in  my  mind  whether,  if  all  the 
visible  or  sensible  universe— estimated  by  Lord  .Kelvin 
as  equivalent  to  about  a  thousand  million  suns— were  all 
concentrated  in  one  body  of  specifiable  density,1  the  stress 
would  not  be  so  great  as  to  produce  a  tendency  toward 
ethereal  disruption ;  which  would  result  in  a  disintegrating 
explosion,  and  a  scattering  of  the  particles  once  more  as  an 
enormous  nebula  and  other  fragments  into  the  depths  of 
space.  For  the  tension  would  be  a  maximum  in  the  interior 
of  such  a  mass;  and,  if  it  rose  to  the  value  of  1033  dynes 
per  square  centimeter,  something  would  have  to  happen. 
I  do  not  suppose  that  this  can  be  the  reason,  but  one  would 
think  there  must  be  some  reason,  for  the  scattered  condition 
of  gravitative  matter. 

Too  little  is  known,  however,  about  the  mechanism  of 
gravitation  to  enable  us  to  adduce  it  as  the  strongest  argu- 
ment in  support  of  the  existence  of  an  ether.  The  oldest 

JOn  doing  the  arithmetic,  however,  I  find  the  necessary  concen- 
tration absurdly  great,  showing  that  such  a  mass  is  quite  insufficient. 


294  MODERN  SCIENCE  READER 

valid  and  conclusive  requisition  of  an  ethereal  medium 
depends  on  the  wave  theory  of  light,  one  of  the  founders 
of  which  was  Dr.  Thomas  Young,  at  the  beginning  of  last 
century. 

No  ordinary  matter  is  capable  of  transmitting  the  undu- 
lations or  tremors  that  we  call  light.  The  speed  at  which 
they  go,  the  kind  of  undulation,  and  the  facility  with  which 
they  go  through  vacuum,  forbid  this. 

So  clearly  and  universally  has  it  been  perceived  that 
waves  must  be  waves  of  something— something  distinct  from 
ordinary  matter— that  Lord  Salisbury,  in  his  presidential 
address  to  the  British  Association  at  Oxford,  criticized  the 
ether  as  little  more  than  a  nominative  case  to  the  verb  to 
undulate.  It  is  truly  that,  though  it  is  also  truly  more  than 
that ;  but  to  illustrate  that  luminif erous  aspect  of  it,  I  will 
quote  a  paragraph  from  the  lecture  of  Clerk  Maxwell's  to 
which  I  have  already  referred : 

The  vast  interplanetary  and  interstellar  regions  will  no  longer  be 
regarded  as  waste  places  in  the  universe  which  the  Creator  has  not 
seen  fit  to  fill  with  the  symbols  of  the  manifold  order  of  His  kingdom. 
We  shall  find  them  to  be  already  full  of  this  wonderful  medium;  so 
full  that  no  human  power  can  remove  it  from  the  smallest  portion  of 
space,  or  produce  the  slightest  flaw  in  its  infinite  continuity.  It 
extends  unbroken  from  star  to  star ;  and  when  a  molecule  of  hydrogen 
vibrates  in  the  dog-star,  the  medium  receives  the  impulses  of  these 
vibrations,  and  after  carrying  them  in  its  immense  bosom  for  several 
years,  delivers  them,  in  due  course,  regular  order,  and  full  tale,  into 
the  spectroscope  of  Mr.  Huggins,  at  Tulse  Hill. 

This  will  suffice  to  emphasize  the  fact  that  the  eye  is  truly 
an  ethereal  sense-organ— the  only  one  which  we  possess,  the 
only  mode  by  which  the  ether  is  enabled  to  appeal  to  us— 
and  that  the  detection  of  tremors  in  this  medium— the 
perception  of  the  direction  in  which  they  go,  and  some  in- 
ference as  to  the  quality  of  the  object  which  has  emitted 
them— cover  all  that  we  mean  by  "sight"  and  "seeing." 

I  pass  then  to  another  function,  the  electric  and  magnetic 
phenomena  displayed  by  the  ether ;  and  on  this  I  will  only 
permit  myself  a  very  short  quotation  from  the  writings  of 


THE  ETHER  OF  SPACE  295 

Faraday,  whose  whole  life  may  be  said  to  have  been  directed 
toward  a  better  understanding  of  these  ethereous  phenom- 
ena. He  is,  indeed,  the  discoverer  of  the  electric  and 
magnetic  properties  of  the  ether  of  space. 

Faraday  conjectured  that  the  same  medium  which  is 
concerned  in  the  propagation  of  light  might  also  be  the 
agent  in  electro-magnetic  phenomena.  He  says: 

For  my  own  part,  considering  the  relation  of  a  vacuum  to  the 
magnetic  force,  and  the  general  character  of  magnetic  phenomena  ex- 
ternal to  the  magnet,  I  am  much  more  inclined  to  the  notion  that  in 
the  transmission  of  the  force  there  is  such  an  action,  external  to  the 
magnet,  than  that  the  effects  are  merely  attraction  and  repulsion  at  a 
distance.  Such  an  action  may  be  a  function  of  the  Eether;  for  it  is 
not  unlikely  that,  if  there  be  an  a3ther,  it  should  have  other  uses  than 
simply  the  conveyance  of  radiation. 

This  conjecture  has  been  amply  strengthened  by  subse- 
quent investigations. 

One  more  function  is  now  being  discovered ;  the  ether  is 
being  found  to  constitute  matter — an  immensely  interesting 
topic,  on  which  there  are  many  active  workers  at  the  present 
time.  I  will  make  a  brief  quotation  from  Professor  J.  J. 
Thomson,  where  he  summarizes  his  own  anticipation  of 
the  conclusion  which  in  one  form  or  another  we  all  see 
looming  before  us,  though  it  has  not  yet  been  completely 
attained,  and  would  not  by  all  be  similarly  expressed: 

The  whole  mass  of  any  body  is  just  the  mass  of  ether  surrounding 
the  body  which  is  carried  along  by  the  Faraday  tubes  associated  with 
the  atoms  of  the  body.  In  fact,  all  mass  is  mass  of  the  ether;  all 
momentum,  momentum  of  the  ether;  and  all  kinetic  energy,  kinetic 
energy  of  the  ether.  This  view,  it  should  be  said,  requires  the  density 
of  the  ether  to  be  immensely  greater  than  that  of  any  known 
substance. 

Yes,  far  denser— so  dense  that  matter  by  comparison  is 
like  gossamer,  or  a  filmy  imperceptible  mist,  or  a  Milky 
Way.  Not  unreal  or  unimportant— a  cobweb  is  not  unreal, 
nor  to  certain  creatures  is  it  unimportant,  but  it  cannot  be 
said  to  be  massive  or  dense ;  and  matter,  even  platinum,  is 
not  dense  when  compared  with  the  ether. 


296  MODERN  SCIENCE  READER 

Not  till  last  year,  however,  did  I  realize  what  the  density 
of  the  ether  must  really  be,1  compared  with  that  modifica- 
tion of  it  which  appeals  to  our  senses  as  matter,  and  which, 
for  that  reason,  engrosses  our  attention.  I  will  return  to 
this  part  of  the  subject  directly. 

Is  there  any  other  function  possessed  by  the  ether,  which, 
though  not  yet  discovered,  may  lie  within  the  bounds  of  pos- 
sibility for  future  discovery  ?  I  believe  there  is,  but  it  is  too 
speculative  to  refer  to,  beyond  saying  that  it  has  been  urged 
as  probable  by  the  authors  of  The  Unseen  Universe,  and 
has  been  tentatively  referred  to  by  Clerk  Maxwell  thus: 

Whether  this  vast  homogeneous  expanse  of  isotropic  matter  is 
fitted  not  only  to  be  a  medium  of  physical  interaction  between  dis- 
tant bodies,  and  to  fulfil  other  physical  functions  of  which,  perhaps, 
we  have  as  yet  no  conception,  but  also ...  to  constitute  the  material 
organism  of  beings  exercising  functions  of  life  and  mind  as  high  or 
higher  than  ours  are  at  present — is  a  question  far  transcending  the 
limits  of  physical  speculation. 

And  there  for  the  present  I  leave  that  aspect  of  the 
subject. 

I  shall  now  attempt  to  illustrate  some  relations  between 
ether  and  matter. 

The  question  is  often  asked:  Is  ether  material?  That  is 
largely  a  question  of  words  and  convenience.  Undoubtedly 
the  ether  belongs  to  the  material  or  physical  universe ;  but 
it  is  not  ordinary  matter.  I  should  prefer  to  say  it  is  not 
"matter"  at  all.  It  may  be  the  substance  or  substratum 
or  material  of  which  matter  is  composed,  but  it  would  be 
confusing  and  inconvenient  not  to  be  able  to  discriminate 
between  matter  on  the  one  hand,  and  ether  on  the  other. 
If  you  tie  a  knot  on  a  bit  of  string,  the  knot  is  composed  of 
string,  but  the  string  is  not  composed  of  knots.  If  you 
have  a  smoke  or  vortex-ring  in  the  air,  the  vortex-ring  is 
made  of  air,  but  the  atmosphere  is  not  a  vortex-ring;  and 
it  would  be  only  confusing  to  say  that  it  was. 

The  essential  distinction  between  matter  and  ether  is  that 

JSee  the  Philosophical  Magasine  for  April,  1907. 


THE  ETHER  OF  SPACE  297 

matter  moves,  in  the  sense  that  it  has  the  property  of  loco- 
motion and  can  effect  impact  and  bombardment;  while 
ether  is  strained,  and  has  the  property  of  exerting  stress 
and  recoil.  All  potential  energy  exists  in  the  ether.  It 
may  vibrate,  and  it  may  rotate,  but  as  regards  locomotion 
it  is  stationary— the  most  stationary  body  we  know— abso- 
lutely stationary,  so  to  speak;  our  standard  of  rest. 

All  that  we  ourselves  can  effect,  in  the  material  universe, 
is  to  alter  the  motion  and  configuration  of  masses  of  matter ; 
we  can  move  matter,  by  our  muscles,  and  that  is  all  we  can 
do  directly:  everything  else  is  indirect.  This  is  worth 
thinking  over  by  those  who  have  not  already  realized  the 
fact. 

But  now  comes  the  question,  how  is  it  possible  for  matter 
to  be  composed  of  ether?  How  is  it  possible  for  a  solid  to 
be  made  out  of  fluid  ?  A  solid  possesses  the  properties  of 
rigidity,  impenetrability,  elasticity,  and  such  like ;  how  can 
these  be  imitated  by  a  perfect  fluid  such  as  the  ether  must 
be?  The  answer  is,  they  can  be  imitated  by  a  fluid  in 
motion;— a  statement  which  we  make  with  confidence  as 
the  result  of  a  great  part  of  Lord  Kelvin's  work. 

It  may  be  illustrated  by  a  few  experiments. 

A  wheel  of  spokes,  transparent  or  permeable  to  matter 
when  stationary,  becomes  opaque  when  revolving,  so  that  a 
ball  thrown  against  it  does  not  go  through,  but  rebounds. 
The  motion  only  affects  permeability  to  matter;  trans- 
parency to  light  is  unaffected. 

A  silk  cord  hanging  from  a  pulley  becomes  rigid  and 
viscous  when  put  into  rapid  motion ;  and  pulses  or  waves 
which  may  be  generated  on  the  cord  travel  along  it  with 
a  speed  equal  to  its  own  velocity,  whatever  that  velocity 
may  be,  so  that  they  appear  very  nearly  to  stand  still. 
This  is  a  case  of  kinetic  rigidity;  and  the  fact  that  the 
wave  transmission  velocity  is  equal  to  the  rotatory  speed  of 
the  material,  is  typical  and  important,  for  in  all  cases  of 
kinetic  elasticity  these  two  velocities  are  of  the  same  order 
of  magnitude. 


298  MODERN  SCIENCE  READER 

A  flexible  chain,  set  spinning,  can  stand  up  on  end  while 
the  motion  continues. 

A  jet  of  water  at  sufficient  speed  can  be  struck  with  a 
hammer,  and  resists  being  cut  with  a  sword. 

A  spinning  disk  of  paper  becomes  elastic  like  flexible 
metal,  and  can  act  like  a  circular  saw.  Sir  William  White 
tells  me  that  in  naval  construction  steel  plates  are  cut  by 
a  rapidly  revolving  disc  of  soft  iron. 

A  vortex-ring,  ejected  from  an  elliptical  orifice,  oscillates 
about  the  stable  circular  form,  as  an  india-rubber  ring 
would  do;  thus  furnishing  a  beautiful  example  of  kinetic 
elasticity,  and  showing  us  clearly  a  fluid  displaying  some 
of  the  properties  of  a  solid. 

A  still  further  example  is  Lord  Kelvin's  model  of  a 
spring  balance,  made  of  nothing  but  rigid  bodies  in  spin- 
ning motion.  See  his  Popular  Lectures  and  Addresses, 
vol.  I,  p.  239,  being  his  "Address  to  Section  A  of  the 
British  Association"  in  1884  at  Montreal. 

If  the  ether  can  be  set  spinning,  therefore,  we  may  have 
some  hope  of  making  it  imitate  the  properties  of  matter 
or  even  of  constructing  matter  by  its  aid.  But  how  are  we 
to  spin  the  ether?  Matter  alone  seems  to  have  no  grip  of 
it.  I  have  spun  steel  discs,  a  yard  in  diameter,  4,000  times 
a  minute,  have  sent  light  round  and  round  between  them, 
and  tested  carefully  for  the  slightest  effect  on  the  ether. 
Not  the  slightest  effect  was  perceptible.  We  cannot  spin 
ether  mechanically. 

But  we  can  vibrate  it  electrically;  and  every  source  of 
radiation  does  that.  An  electrified  body,  in  sufficiently 
rapid  vibration,  is  the  only  source  of  ether-waves  that  we 
know;  and  if  an  electric  charge  is  suddenly  stopped,  it 
generates  the  pulses  known  as  X-rays,  as  the  result  of  the 
collision.  Not  speed,  but  sudden  change  of  speed,  is  the 
necessary  condition  for  generating-waves  in  the  ether  by 
electricity. 

We  can  also,  it  is  believed,  infer  some  kind  of  rotary 
motion  in  the  ether ;  though  we  have  no  such  obvious  means 


THE  ETHER  OF  SPACE  299 

of  detecting  the  spin  as  is  furnished  by  vision  for  detect- 
ing some  kinds  of  vibration.  It  is  supposed  to  exist  when- 
ever we  put  a  charge  into  the  neighborhood  of  a  magnetic 
pole.  Round  the  line  joining  the  two,  the  ether  is  spinning 
like  a  top.  I  do  not  say  it  is  spinning  fast :  that  is  a  ques- 
tion of  its  density;  it  is,  in  fact,  spinning  with  excessive 
slowness,  but  it  is  spinning  with  a  definite  moment  of 
momentum.  J.  J.  Thomson's  theory  makes  its  moment  of 
momentum  exactly  equal  to  e  m,  the  product  of  charge 
and  pole;  the  charge  being  measured  electrostatically  and 
the  pole  magnetically. 

How  can  this  be  shown  experimentally?  Suppose  we 
had  a  spinning  top  enclosed  in  a  case,  so  that  the  spin  was 
unrecognizable  by  ordinary  means,  it  could  be  detected  by 
its  gyrostatic  behavior  to  force.  If  allowed  to  "precess" 
it  will  respond  by  moving  perpendicularly  to  a  deflecting 
force.  So  it  is  with  the  charge  and  the  magnetic  pole.  Try 
to  move  either  suddenly,  and  it  immediately  sets  off  at 
right  angles  to  the  force.  A  moving  charge  is  a  current, 
and  the  pole  and  the  current  try  to  revolve  round  one 
another— a  true  gyrostatic  action  due  to  the  otherwise  un- 
recognizable ethereal  spin.  The  fact  of  such  magnetic  rota- 
tion was  discovered  by  Faraday. 

I  know  that  it  is  usually  worked  out  in  another  way,  in 
terms  of  lines  of  force  and  the  rest  of  the  circuit;  but  I 
am  thinking  of  a  current  as  a  stream  of  projected  charges ; 
and  no  one  way  of  regarding  such  a  matter  is  likely  to 
exhaust  the  truth,  or  to  exclude  other  modes  which  are 
equally  valid.  Anyhow,  in  whatever  way  it  is  regarded, 
it  is  an  example  of  the  three  rectangular  vectors. 

The  three  vectors  at  right  angles  to  each  other,  which 
may  be  labelled  Current,  Magnetism  and  Motion,  respec- 
tively, or  more  generally  E.,  H.  and  V.,  represent  the 
quite  fundamental  relation  between  ether  and  matter,  and 
constitute  the  link  between  Electricity,  Magnetism  and 
Mechanics.  Where  any  two  of  these  are  present,  the  third 
is  a  necessary  consequence.  This  principle  is  the  basis  of 


300  MODERN  SCIENCE  READER. 

all  dynamos,  of  electric  motors,  of  light,  of  telegraphy,  and 
of  most  other  things.  Indeed,  it  is  a  question  whether  it 
does  not  underlie  everything  that  we  know  in  the  whole  of 
the  physical  sciences ;  and  whether  it  is  not  the  basis  of  our 
conception  of  the  three  dimensions  of  space. 

Lastly,  we  have  the  fundamental  property  of  matter 
called  inertia,  which,  if  I  had  time,  I  would  show  could  be 
explained  electromagnetically,  provided  the  ethereal  dens- 
ity is  granted  as  of  the  order  of  1012  grams  per  cubic 
centimeter.  The  elasticity  of  the  ether  would  then  have 
to  be  of  the  order  of  1033  c.g.s. ;  and  if  this  is  due  to  in- 
trinsic turbulence,  the  speed  of  the  whirling  or  rotational 
elasticity  must  be  of  the  same  order  as  the  velocity  of  light. 
This  follows  hydrodynamically ;  in  the  same  sort  of  way 
as  the  speed  at  which  a  pulse  traveling  on  a  flexible  run- 
ning endless  cord,  whose  tension  is  entirely  due  to  the 
centrifugal  force  of  the  motion,  is  precisely  equal  to  the 
velocity  of  the  cord  itself.  And  so,  on  our  present  view, 
the  intrinsic  energy  of  constitution  of  the  ether  is  incred- 
ibly and  portentously  great ;  every  cubic  millimeter  of  space 
possessing  what,  if  it  were  matter,  would  be  a  mass  of  a 
thousand  tons,  and  an  energy  equivalent  to  the  output  of  a 
million  horse-power  station  for  forty  million  years. 

The  universe  we  are  living  in  is  an  extraordinary  one; 
and  our  investigation  of  it  has  only  just  begun.  We  know 
that  matter  has  a  psychical  significance,  since  it  can  consti- 
tute brain,  which  links  together  the  physical  and  the 
psychical  worlds.  If  any  one  thinks  that  the  ether,  with 
all  its  massiveness  and  energy,  has  probably  no  psychical 
significance,  I  find  myself  unable  to  agree  with  him. 

SUPPLEMENTARY  REMARKS  CONCERNING  DENSITY  OF  ETHER 

I  observe  that  it  is  surmised  by  at  least  one  thoughtful 
and  friendly  critic  that  in  speaking  of  the  immense  density 
or  massiveness  of  ether,  and  the  absurdly  small  density  or 
specific  gravity  of  gross  matter  by  comparison,  I  intended 
to  signify  that  matter  is  a  rarefaction  of  the  ether.  That, 


THE  ETHER  OF  SPACE  301 

however,  was  not  my  intention.  The  view  I  advocate  is 
that  the  ether  is  a  perfect  continuum,  an  absolute  plenum, 
and  that,  therefore,  no  local  rarefaction  is  possible.  The 
ether  inside  matter  is  just  as  dense  as  the  ether  outside, 
and  no  denser.  A  material  unit— say  an  electron— is  only 
a  peculiarity  or  singularity  of  some  kind  in  the  ether  itself, 
which  is  of  perfectly  uniform  density  everywhere.  What 
we  sense  as  matter  is  an  aggregate  or  grouping  of  an 
enormous  number  of  such  units. 

How,  then,  can  we  say  that  matter  is  millions  of  times 
rarer  or  less  substantial  than  the  ether  of  which  it  is  essen- 
tially composed  ?  Those  who  feel  any  difficulty  here  should 
bethink  themselves  of  what  they  mean  by  the  average  or 
aggregate  density  of  any  discontinuous  system,  such  as  a 
powder,  or  a  gas,  or  a  precipitate,  or  a  snowstorm,  or  a 
cloud,  or  a  Milky  Way. 

Lord  Kelvin  has  estimated  and,  indeed,  proved  that  the 
aggregate  density  of  the  whole  material  cosmos  within 
recognizable  gravitational  reach  of  us  must  be  infinitesimal ; 
in  other  words,  that  the  amount  of  matter  In  space,  how- 
ever prodigious  it  may  be,  must  be  infinitely  less  than  the 
volume  of  space  it  occupies.  And  even  of  the  visible  cos- 
mos—that is  to  say,  of  the  material  clustering  within  reach 
of  our  aided  organs  of  vision — the  density,  though  cer- 
tainly not  infinitesimal,  is  exceedingly  small. 

It  may  be  clearer  if  I  give  some  actual  numbers.  Lord 
Kelvin  estimates  the  amount  of  matter  within  reach  of  the 
largest  telescopes— say  within  a  parallax  of  -nnnr  second  of 
arc,  corresponding  to  a  radius  of  3  x  1016  kilometers — as 
equivalent  to  a  thousand  million  of  our  suns ;  that  is,  to  a 
total  mass  of  1.5  x  1036  tons  distributed  through  a  volume 
of  1.12  x  1059  cubic  meters.  So  the  density  of  the  visible 
cosmos  comes  out  of  the  order  of  10  ~23  of  that  of  water. 

The  masses  themselves  seem  likely  to  be  in  the  main  dis- 
tinctly of  greater  density  than  water;  but  grouped,  or  in 
the  aggregate,  they  are  excessively  "  rare  "—far  rarer  than 
the  residual  gas  in  the  highest-known  vacuum.  The  whole 


302  MODERN  SCIENCE  READER 

visible  cosmos  is,  in  fact,  as  much  rarer  than  what  we  call 
a  high  vacuum  (say,  the  hundred-millionth  of  an  atmo*- 
phere)  as  that  vacuum  is  rarer  than  lead.  If  it  be  urged 
that  it  is  unfair  to  compare  an  obviously  discrete  assemblage 
like  the  stars,  with  an  apparently  continuous  substance  like 
air  or  lead,  the  answer  is  that  it  is  entirely  and  accurately 
fair;  since  air,  and  every  other  known  form  of  matter,  is 
essentially  an  aggregate  of  particles,  and  since  it  is  always 
their  average  density  that  we  mean.  We  do  not  even  know 
for  certain  their  individual  atomic  density. 

The  phrase,  "specific  gravity  or  density  of  a  powder"  is 
ambiguous.  It  may  mean  the  specific  gravity  of  the  dry 
powder  as  it  lies,  like  snow;  or  it  may  mean  the  specific 
gravity  of  the  particles  of  which  it  is  composed,  like  ice. 

So  also  with  regard  to  the  density  of  matter,  we  might 
mean  the  density  of  the  fundamental  material  of  which  its 
units  are  made — which  would  be  ether ;  or  we  might,  and 
in  practice  do,  mean  the  density  of  the  aggregate  lump 
which  we  can  see  and  handle;  that  is  to  say,  of  water,  or 
iron,  or  lead,  as  the  case  may  be. 

In  saying  that  the  density  of  matter  is  small,  I  mean,  of 
course,  in  this  last,  the  usual,  sense.  In  saying  that  the 
density  of  ether  is  great,  I  mean  that  the  actual  stuff  of 
which  these  highly  porous  aggregates  are  composed  is  of 
immense,  of  well-nigh  incredible  density.  It  is  only  another 
way  of  saying  that  the  ultimate  units  of  matter  are  few 
and  far  between— i.e.,  that  they  are  excessively  small  as 
compared  with  the  distances  between  them;  just  as  the 
planets  of  the  solar  system,  or  worlds  in  the  sky,  are  few 
and  far  between— the  intervening  distances  being  enormous 
as  compared  with  the  portions  of  space  actually  occupied 
by  lumps  of  matter. 

Here  it  may  be  noted  that  it  is  possible  to  argue  that  the 
density  of  a  continuum  is  necessarily  greater  than  the  dens- 
ity of  any  disconnected  aggregate :  certainly  of  any  assem- 
blage whose  particles  are  actually  composed  of  the  material 
of  the  continuum.  Because  the  former  is  "all  there," 


THE  ETHER  OF  SPACE  303 

everywhere,  without  break  or  intermittance  of  any  kind; 
while  the  latter  has  gaps  in  it— it  is  here,  and  there,  but 
not  everywhere. 

Indeed,  this  very  argument  was  used  long  ago  by  that 
notable  genius,  Robert  Hooke ;  and  I  quote  a  passage  which 
Professor  Poynting  has  discovered  in  his  collected  posthu- 
mous works,  and  kindly  copied  out  for  me : 

As  for  matter,  that  I  conceive  in  its  essence  to  be  immutable,  and 
its  essence  being  expatiation  determinate,  it  cannot  be  altered  in  its 
quantity,  either  by  condensation  or  rarefaction;  that  is,  there  cannot 
be  more  or  less  of  that  power  or  reality,  whatever  it  be,  within  the 
same  expatiation  or  content;  but  every  equal  expatiation  contains,  is 
filled,  or  is  an  equal  quantity  of  materia;  and  the  densest  or  heaviest, 
or  most  powerful  body  in  the  world  contains  no  more  materia  than  that 
which  we  conceive  to  be  the  rarest,  thinnest,  lightest,  or  least  powerful 
body  of  all ;  as  gold  for  instance,  and  (Ether,  or  the  substance  that  fills 
the  cavity  of  an  exhausted  vessel,  or  cavity  of  the  glass  of  a  barom- 
eter above  the  quicksilver.  Nay,  as  I  shall  afterwards  prove,  this 
cavity  is  more  full,  or  a  more  dense  body  of  asther,  in  the  common 
sense  or  acception  of  the  word,  than  gold  is  of  gold,  bulk  for  bulk; 
and  that  because  the  one,  viz.,  the  mass  of  aether,  is  all  aether :  but  the 
mass  of  gold,  which  we  conceive,  is  not  all  gold;  but  there  is  an 
intermixture,  and  that  vastly  more  than  is  commonly  supposed,  of 
aether  with  it;  so  that  vacuity,  as  it  is  commonly  thought,  or  errone- 
ously supposed,  is  a  more  dense  body  than  the  gold  as  gold.  But  if 
we  consider  the  whole  content  of  the  one  with  that  of  the  other, 
within  the  same  or  equal  quantity  of  expatiation,  then  are  they  both 
equally  containing  the  materia  or  body. — From  the  Posthumous 
Works  of  Robert  HooTce,  H.D.,  F.E.S.,  1705,  pages  171  and  172  (as 
copied  in  "Memoir  of  Dalton,"  ~by  Angus  Smith). 

Newton's  contemporaries  do  not  shine  in  facility  and 
clearness  of  expression,  as  he  himself  did,  but  Professor 
Poynting  interprets  the  above  singular  attempt  at  utter- 
ance thus: 

All  space  is  filled  with  equally  dense  materia.  Gold  fills  only  a 
small  fraction  of  the  space  assigned  to  it,  and  yet  has  a  big  mass. 
How  much  greater  must  be  the  total  mass  filling  that  space! 

The  tacit  assumption  here  made  is  that  the  particles  of 
the  aggregate  are  all  composed  of  one  and  the  same  con- 
tinuous substance— practically  that  matter  is  made  of 


304  MODERN  SCIENCE  READER 

ether;  and  that  assumption,  in  Hooke's  day,  must  have 
been  only  a  speculation.  But  it  is  the  kind  of  speculation 
which  time  is  justifying— it  is  the  kind  of  truth  which  we 
all  feel  to  be  in  process  of  establishment  now. 

We  do  not  depend  on  that  sort  of  argument,  however; 
what  we  depend  on  is  experimental  measure  of  the  mass, 
and  mathematical  estimate  of  the  volume,  of  the  electron. 
For  calculation  shows  that  however  the  mass  be  accounted 
'for,  whether  electrostatically  or  magnetically,  or  hydrody- 
namically,  the  estimate  of  ratio  of  mass  to  effective  volume 
can  differ  only  in  a  numerical  coefficient  and  cannot  differ 
as  regards  order  of  magnitude.  The  only  way  out  of  this 
conclusion  would  be  the  discovery  that  the  negative  electron 
is  not  the  real  or  the  main  matter-unit,  but  is  only  a  sub- 
sidiary ingredient,  whereas  the  main  mass  is  the  more 
bulky  positive  charge.  That  last  hypothesis,  however,  is 
at  present  too  vague  to  be  useful.  Moreover,  the  mass  of 
such  a  charge  would  in  that  case  be  unexplained,  and  would 
need  a  further  step ;  which  would  probably  land  us  in 
much  the  same  sort  of  ethereal  density  as  is  involved  in  the 
estimate  which  I  have  based  on  the  more  familiar  and 
tractable  negative  electron. 

It  may  be  said,  why  assume  any  finite  density  for  the 
ether  at  all?  Why  not  assume  that,  as  it  is  infinitely  con- 
tinuous, so  it  is  infinitely  dense— whatever  that  may  mean 
—and  that  all  its  properties  are  infinite? 

This  might  be  possible  were  it  not  for  the  velocity  of 
light.  By  transmitting  waves  at  a  finite  and  measurable 
speed,  the  ether  has  given  itself  away,  and  has  let  in  all  the 
possibilities  of  calculation  and  numerical  statement.  Its 
properties  are  thereby  exhibited  as  essentially  finite — how- 
ever infinite  the  whole  extent  of  it  may  turn  out  to  be. 


UNSOLVED  PROBLEMS  OF 
CHEMISTRY1 

BY  TEA  EEMSEN,   PH.  D. 

President    of    Johns    Hopkins    University 

THE  first  duty  of  the  chemist  is  to  examine  every  kind  of 
matter  accessible  to  him  and  to  determine  whether  it  is  an 
element  or  not.  If  it  is  not,  and  this  is  usually  the  case 
as  regards  the  things  found  in  nature,  his  next  duty  is  to 
attack  the  compound  in  every  way  that  is  likely  to  lead  to 
its  decomposition,  and  when  he  reaches  a  substance  from 
which  he  cannot  get  simpler  ones,  he  calls  this  an  element. 
Thus  iron,  copper,  gold,  silver,  tin,  hydrogen,  and  oxygen 
are  elements.  None  of  these  can  be  decomposed  by  the 
means  at  present  at  the  command  of  the  chemist.  They 
are  like  the  letters  of  a  language  in  some  respects.  Words 
can  be  decomposed  or  resolved  into  letters,  but  letters  are 
the  elements  of  language.  What  elements  are  in  the 
earth,  in  the  air,  in  water?  An  immense  amount  of  work 
has  been  done  that  has  had  for  its  object  the  answering  of 
this  question.  The  earth  has  been  ransacked  almost  from 
pole  to  pole.  The  air  from  all  sorts  of  localities  has  been 
examined.  The  waters,  from  ocean,  rivers,  and  springs, 
have  been  made  to  stand  and  answer  the  searching  ques- 
tions of  the  chemist ;  and  animals  and  plants  have  been 
compelled  to  give  up  their  secrets— or  some  of  them. 

What  is  the  result?  In  brief,  it  is  this:  Although  we 
find  an  infinite  number  of  kinds  of  matter,  all  of  these  can 
be  resolved  into  a  comparatively  small  number  of  elements. 
Indeed,  not  more  than  a  dozen  of  these  elements  enter  into 
the  composition  of  the  things  that  are  at  all  common.  But 
by  going  into  out-of-the-way  corners  rare  things  have  been 

Published  in  NcClure's  Magazine,  February,  1901. 
20  805 


306  MODERN  SCIENCE  READER 

found,  and  from  these,  in  turn,  rare  elements  have  been 
obtained.  Altogether,  between  seventy  and  eighty  ele- 
ments have  been  found.  Additions  are  made  to  the  list 
from  time  to  time ;  and,  occasionally,  one  of  the  substances 
supposed  to  be  an  element  is  found  to  be  capable  of  decom- 
position, and  it  therefore  becomes  necessary  to  strike  it 
from  the  list  of  elements. 

Out  of  these  simplest  forms  of  matter  everything  that 
we  see  or  feel,  or  are  in  any  way  cognizant  of,  is  made  up. 
But  now  arises  the  deep  question:  What  is  an  element? 
To  this  question  chemists  are  not  able  to  give  an  answer. 
The  relations  of  the  elements  to  one  another  form  one  of 
the  unsolved  problems  of  chemistry.  It  may  be  that  they 
are  not  related  at  all,  but  that  each  one  is  an  independent 
form  of  matter.  There  are,  however,  indications  of  family 
relationships  between  them  that  have  long  been  the  subject 
of  investigation.  The  elements  fall  into  groups,  the  mem- 
bers of  which  resemble  one  another  very  closely  in  some 
respects.  Thus,  for  example,  phosphorus  and  arsenic  con- 
duct themselves,  in  general,  alike  toward  other  elements. 
They  combine  with  them  to  form  compounds  that  are  very 
much  alike — so  much  so  that  in  some  cases  it  is  difficult 
to  tell  them  apart.  These  elements  are  said  to  belong  to 
the  same  family.  The  family  traits  are  easily  recognized 
in  them.  Similar  relationships  are  met  with  throughout 
the  entire  list  of  elements.  This  subject  has  been  beauti- 
fully worked  out  by  the  Russian  chemist  Mendel  eef  and 
the  German,  Lothar  Meyer.  The  former,  indeed,  pointed 
out,  thirty  years  ago,  that  some  of  the  families  are  not 
complete.  There  were  a  number  of  vacant  chairs.  He 
was  able  to  predict  the  discovery  of  some  of  these  missing 
members  and  to  describe  them  in  detail.  Three  of  these 
have  since  been  discovered,  and  they  have  been  found  to 
answer  the  description  given  by  Mendeleef  before  their 
discovery.  Now  that  the  way  has  been  pointed  out,  it  is  a 
comparatively  simple  thing  to  predict  the  discovery  of 
other  elements,  The  vacant  chairs  are  there,  but  though 


PROBLEMS   OF  CHEMISTRY  307 

the  elements  that  are  eventually  to  occupy  them  are  prob« 
ably  hidden  away  somewhere  in  the  earth,  they  have  thus 
far  eluded  the  chemist. 

As  regards  the  character  of  the  relationships  that  exist 
between  the  elements,  it  is  difficult,  or,  rather,  quite  impos- 
sible, to  speak  with  confidence.  Apparently,  the  elements 
are  brothers  and  sisters.  We  want  to  find  the  fathers  and 
mothers.  But  it  appears  that  they  are  no  longer  living. 
The  plain  question  that  we  cannot  help  asking  is :  Have  the 
elements  existed  from  the  beginning  of  time,  or  have  they 
been  formed  from  a  smaller  number  of  simpler  forms  of 
matter?  Of  course,  one  can  speculate  on  such  a  subject, 
but  can  one  speculate  profitably?  It  may  as  well  be 
acknowledged  at  once  that  we  know  practically  nothing  in 
regard  to  the  origin  of  the  elements,  or  of  the  cause  of  the 
relationships  that  are  so  easily  recognized. 

It  has  been  suggested  that  the  elements  are  tfie  products 
of  an  evolutionary  process  that  has  been  in  progress  from 
the  beginning,  and  that  they  all  owe  their  existence  to  a 
primordial  form  of  matter,  simpler  than  any  one  of  the 
so-called  elements.  Some  evidence  in  favor  of  this  view 
seems  to  be  furnished  by  the  spectroscopic  examination  of 
celestial  bodies.  The  nebulae  have  been  shown  to  contain 
the  smallest  number  of  our  chemical  elements;  the  hotter 
stars  are  somewhat  more  complex;  in  the  colored  stars  and 
the  sun  a  large  number  of  elements  appear;  while  the 
planets  are  the  most  complex.  The  complexity  seems  to 
depend  upon  the  temperature.  The  higher  the  tempera- 
ture, the  smaller  the  number  of  kinds  of  matter  present. 
Now,  may  it  not  be  that  the  elements  known  to  us  are 
derived  from  simpler  forms,  or  from  one  single  simplest 
form?  We  can  only  answer— it  may.  If  this  is  the  true 
conception  of  the  relations  between  the  elements,  then  "in 
the  beginning"  space  must  have  been  filled  with  an  incan- 
descent vapor  made  up  of  the  simplest  form  of  matter.  As 
this  has  cooled,  it  has  taken  other  forms,  and  some  of  these 
are  the  things  we  now  call  elements.  But  this  shows  how 


308  MODERN  SCIENCE  READER 

easy  it  is  to  relapse  into  the  ways  of  our  forefathers  and 
let  our  imaginations  run  wild. 

ELEMENTS  OF  PLANTS  AND  ANIMALS 

Another  unsolved  problem  of  chemistry  is  that  presented 
by  the  fundamental  constituents  of  plants  and  animals. 
No  one  knows  better  than  the  chemist  that  all  living  things 
are  ''fearfully  and  wonderfully  made."  Plants  take  ma- 
terials of  various  kinds  from  the  air  and  from  the  earth, 
and  work  them  up  in  proper  shape  for  their  growth.  In 
turn,  animals  take  parts  of  some  plants  or  parts  of  some 
animals,  and  work  them  up  so  that  they  become  part  and 
parcel  of  the  animal  bodies.  Life  and  growth  of  plant 
and  animal  depend  upon  this  power  to  convert  food  into 
other  things  that  can  take  their  proper  places  in  the  body. 
Chemical  change  is  the  beginning  of  life.  But  what  are 
these  things  that  are  formed  within  the  plant  and  animal? 
That  is  a  hard  question  to  answer ;  and,  indeed,  the  answer 
would  be  confusing.  All  that  need  be  said  is  that  among 
these  things  are  the  fats,  sugar,  starch,  cellulose,  and  a 
group  of  important  compounds  called  proteids.  Besides 
these,  there  are  innumerable  substances  found  both  in 
plants  and  animals.  Naturally,  chemists  are  interested  in 
these  things,  and  they  have  given,  and  are  giving,  much 
time  to  their  investigation.  It  is  only  through  such  study 
that  we  can  hope  ever  to  gain  any  conception  of  the 
changes  that  are  taking  place  in  living  things,  or  of  the 
nature  of  life  in  its  various  forms. 

Of  the  substances  mentioned,  the  fats  are  relatively  the 
simplest,  and  they  are,  accordingly,  pretty  well  understood. 
It  is  interesting  to  note  in  passing  that  the  first  and  the 
most  important  chemical  investigation  in  fats  was  carried 
out  at  the  beginning  of  this  century  by  the  French  chemist 
Chevreul,  who  died  only  a  few  years  ago  at  the  age  of  103, 
having  kept  in  harness  to  the  last.  Regarding  our  knowl- 
edge of  fats,  it  is  safe  to  say  that  we  know  enough  about 
them  to  be  able  to  see  how  one  could,  starting  with  carbon, 


PROBLEMS   OF   CHEMISTRY  309 

hydrogen,  and  oxygen,  which  are  the  only  elementary  sub- 
stances found  in  the  fats — how  one  could  make  in  the  lab- 
oratory the  same  fats  that  occur  in  living  things.  No  one 
has  ever  done  this,  but  it  appears  highly  probable  that,  with 
unlimited  time  at  one 's  disposal,  it  could  be  clone  by  making 
use  of  methods  that  are  made  use  of  every  day  in  the  lab- 
oratory. Not  many  years  ago  that  statement  would  have 
been  challenged.  The  constituents  of  plants  and  animals 
were  supposed  to  be  entirely  different  from  the  constituents 
of  the  inanimate  inorganic  parts  of  the  earth,  and  it  was 
further  supposed  that  those  substances  which  are  elaborated 
under  the  influence  of  the  life-process  cannot  be  formed 
without  this  influence.  This  may  be  true  of  the  most  com- 
plex constituents  of  plants  and  animals,  but  it  is  certainly 
not  true  of  some  of  the  simpler  of  these  constituents.  For 
example,  urea,  one  of  the  most  characteristic  substances 
formed  in  the  animal  body,  was  made  in  the  laboratory  in 
1828,  by  a  method  which  was  entirely  independent  of  the 
life-process;  and  since  that  time  innumerable  other  sub- 
stances which  are  characteristic  products  of  the  life-process 
have  been  made  artificially.  So  that,  as  we  know  very  well 
what  fats  are,  and  can  make  substances  of  the  same  kind 
in  the  laboratory,  there  is  nothing  out  of  the  way  in  saying 
that  the  fats  could  probably  be  made  artificially.  Let  us 
assume  that  they  can  be.  What  then? 

Next  in  order  of  complexity  come  the  so-called  carbo- 
hydrates, which  include  the  sugars,  starch,  and  cellulose. 
Is  it  "highly  probable"  that  the  chemist  can  build  these 
up  out  of  the  elements  in  the  laboratory?  Thanks  to 
Emil  Fischer,  of  Berlin,  we  can  now  almost  say  that  sugar 
is  not  an  unsolved  problem.  Within  the  last  few  years 
more  has  been  done  to  clear  up  the  problem  of  the  sugars 
than  in  all  preceding  time  put  together.  One  of  the  sim- 
plest sugars  has  been  prepared  artificially  in  the  laboratory, 
and  the  relations  between  the  others  have  been,  to  a  large 
extent,  revealed. 

But  the  sugars  are  simple  things  compared  with  starch. 


310  MODERN  SCIENCE  READER 

Starch  is  an  unsolved  problem.  It  is  of  the  highest  im- 
portance in  Nature.  Its  wide  distribution  among  plants 
and  the  part  that  it  plays  as  a  constituent  of  foods  show 
this.  What  is  it  ?  Of  course,  if  we  say  it  is  a  carbohydrate, 
we  have  made  the  whole  subject  clear !  The  truth  is  we 
know  very  little  about  it,  in  spite  of  the  large  amount  of 
work  that  has  been  done  on  it.  In  what  has  been  done 
there  is  little  promise  of  success,  though  the  chemical 
optimist  hopes,  even  in  the  face  of  starch.  I  confess  to 
being  a  moderate  optimist.  If  asked  why  I  hope  in  this 
case,  I  could  only  answer,  "I  hope— that  is  all." 

Let  us  take  the  next  step.  This  brings  us  to  cellulose,  a 
substance  of  very  great  importance  for  all  plants.  It 
forms,  as  it  were,  their  skeletons.  Just  as  animals  are 
built  upon  a  basis  of  bone,  so  plants  are  built  upon  a  basis 
of  cellulose.  It  is  that  constituent  of  plants  that  gives  them 
form  and  that  enables  them  to  resist  the  disintegrating  in- 
fluences to  which  they  are  subject  in  Nature.  When  a 
piece  of  wood  is  treated  with  certain  active  substances, 
" chemicals"  as  they  are  called  by  the  outside  world,  many 
of  the  constituents  are  destroyed  and  removed,  and,  finally, 
what  is  known  as  wood-pulp  remains.  This  is  mainly 
cellulose.  As  is  well  known,  large  quantities  of  paper  are 
made  from  this  pulp.  Paper  is,  in  fact,  more  or  less  pure 
cellulose.  Every  plant  contains  cellulose,  and  without  it 
the  plants  could  not  exist.  It  seems  as  though  a  chemist 
ought  to  feel  humiliated  to  have  to  confess  that  even  less  is 
known  about  cellulose  than  about  starch.  There  appears 
to  be  some  reason  for  believing  that  it  is  distantly  related 
to  starch,  but  that  is  about  all  we  can  say.  It  is  probably 
enormously  complicated.  To  be  sure,  it  contains  only  the 
three  elements,  carbon,  hydrogen,  and  oxygen,  but  these 
three  elements  can  combine  with  one  another  in  thousands 
of  different  ways,  forming,  on  the  one  hand,  relatively 
simple  products,  and,  on  the  other,  products  of  such  com- 
plexity that  before  them  the  chemist  can  only  stand  and 
wonder.  Cellulose  belongs  to  the  latter  class. 


PROBLEMS   OF   CHEMISTRY  311 

THE  AWESOME  PROTEIDS 

Finally,  let  us  remove  our  hats  and  shoes,  and,  bowing 
low,  ask  with  bated  breath:  What  about  the  proteids? 
What  about  them,  indeed  ?  Let  us,  rather,  go  back  to  cellu- 
lose and  starch  and  recover  our  courage  and  our  heads. 
This  atmosphere  is  stifling.  I  always  feel  like  running 
away  when  any  one  begins  to  talk  about  proteids  in  my 
presence,  and  here  I  am,  trying  to  write  something  about 
them.  I  ought  to  be  ashamed  of  myself.  Quoting  from  a 
text-book  of  physiology:  " These  [proteids]  form  the  prin- 
cipal solids  of  the  muscular,  nervous,  and  glandular  tissues, 
of  the  serum  of  blood,  of  serous  fluids,  and  of  lymph." 
That  tells  the  story.  What  could  we  do  without  them  ?  It 
is  not  for  me  to  say  what  we  know  about  proteids.  In  my 
youth  I  had  a  desire  to  attack  these  dragons,  but  now  I 
am  afraid  of  them.  Fortunately,  there  is  no  occasion  here 
for  enlarging  upon  them.  I  only  want  to  make  clear  the 
fact  that  they  are  unsolved  problems  of  chemistry;  and, 
let  me  add,  they  are  likely  to  remain  such  for  generations 
to  come.  Yet  every  one  who  knows  anything  about  chem- 
istry and  physiology  knows  that  these  proteids  must  be 
understood,  before  we  can  hope  to  have  a  clear  conception 
of  the  chemical  processes  of  the  human  body.  Fortunately 
for  us,  there  are  always  some  chemists  who  delight  in 
working  upon  the  most  difficult  problems  and  are  not  will- 
ing to  take  "No"  for  an  answer.  So  that  there  is  always 
some  one  working  on  the  proteids,  and  something  is  coming 
of  it. 

In  the  field  of  synthetic  chemistry  perhaps  the  most  im- 
portant problem  among  those  that  are  unsolved  is  that 
presented  by  protoplasm.  I  have  recently  heard  of  a 
school,  and  a  primary  school  at  that,  where  the  small  chil- 
dren are  introduced  to  the  mysteries  of  life  by  being  told 
"all  about"  protoplasm.  If  I  were  a  pupil  in  that  school, 
I  might  be  able  to  tell  my  readers  what  protoplasm  is,  but, 
as  I  have  not  that  privilege,  I  shall  have  to  acknowledge 


312  MODERN  SCIENCE  READER 

that  I  know  very  little  about  it.  In  fact,  it  is  a  substance, 
or  a  mixture  of  substances,  with  which  the  chemist  can  do 
very  little.  Great  interest  has  been  taken  in  all  that  per- 
tains to  protoplasm,  because  it  is  so  directly  connected  with 
life.  The  simplest  organisms  are  the  amoebce.  These  may 
be  regarded  as  representing  life  reduced  to  its  lowest  form. 
Now  an  amoebce  "is  wholly  or  almost  wholly  protoplasm." 
' '  It  lives,  moves,  eats,  grows,  and,  after  a  time,  dies,  having 
been,  during  its  whole  life,  hardly  anything  more  than  a 
minute  lump  of  protoplasm" —  (Foster).  Regarded  as  a 
chemical  substance,  it  contains  the  elements  oxygen,  hydro- 
gen, nitrogen,  carbon,  and  sulphur  in  fairly  constant  pro- 
portions. It  would  be  a  great  day  for  chemistry  if  a 
chemist  should  succeed  in  putting  together,  and  causing 
to  unite,  the  above-named  elements  in  the  proportions  in 
which  they  are  present  in  protoplasm,  and  he  should  find 
that  he  had  made  protoplasm  artificially.  If  this  artificial 
protoplasm  should  move  and  eat  and  grow,  he  would 
deserve  to  be  ranked  with  Pygmalion  of  old.  What  are 
the  prospects? 

In  the  first  place,  protoplasm  does  not  appear  to  be  a 
single  substance,  but  a  mixture  of  substances.  It  contains 
something  that  is  derived  from  a  proteid,  something  else 
derived  from  a  fat,  and  still  a  third  something  derived  from 
a  carbohydrate.  Perhaps  these  three  things  are  chemically 
united  with  one  another,  and  not  simply  mixed.  The  prob- 
lem presented  to  the  chemist  is  one  of  the  greatest  difficulty. 
It  would  be  necessary  for  him  to  determine  exactly  what 
proteid,  what  fat,  and  what  carbohydrate  are  essential  to 
the  existence  of  protoplasm;  then  to  bring  these  together, 
and  show  that  the  substance  thus  obtained  is  identical  with 
protoplasm.  This  might  be  accomplished,  and  yet  the 
protoplasm  obtained  not  be  a  living  thing ;  for  there  is  dead, 
as  well  as  living  protoplasm.  There  is  no  evidence  that 
any  chemist  is  engaged  in  attempts  to  make  protoplasm  in 
the  laboratory.  Possibly  sone  are  dreaming  of  this  prob- 
lem, but  dreams  are  generally  harmless,  and  sometimes  they 


PROBLEMS   OF   CHEMISTRY  313 

are  pleasant,  and,  indeed,  useful.  Before  we  can  under- 
stand, if  we  ever  are  to  understand,  the  difference  between 
a  living  and  a  dead  tissue,  we  must  understand  what 
protoplasm  is,  and  our  chances  of  solving  the  problem  pre- 
sented by  this  important  basis  of  life  are  extremely  poor. 
Still,  we  may  hope  to  get  nearer  its  solution  by  continued 
investigation,  and  we  shall  have  to  be  satisfied  with  small 
returns  for  our  labor. 

Chemistry  has  to  deal  with  the  composition  of  things, 
and  the  changes  in  the  composition  of  things,  and  all  that 
pertains  to  these  subjects.  Changes  in  composition  are 
often  brought  about  by  raising  the  temperature.  To  take 
a  comparatively  simple,  though  not  a  familiar,  example, 
water  is  a  compound  of  the  elements  hydrogen  and  oxygen. 
When  this  is  heated,  it  is  converted  into  water-vapor. 
When  this  vapor  is  heated  to  4,500  degrees  Fahrenheit,  it 
is  resolved  into  hydrogen  and  oxygen.  At  this  tempera- 
ture the  compound,  water,  cannot  exist.  On  the  other 
hand,  when  hydrogen  and  oxygen  are  brought  together  at 
ordinary  temperatures,  they  do  not  combine  to  form  water, 
unless  a  spark  or  a  flame  is  brought  in  contact  with  the 
mixture,  when  a  violent  explosion  occurs,  and  this  is  the  sig- 
nal of  the  chemical  union  of  the  two  elements  to  form  water. 
Again,  when  wood  is  heated,  it  gives  off  gases  and  liquids, 
and  at  last  there  is  nothing  left  but  charcoal,  which  is  one 
form  of  the  element  carbon.  It  is  plain  that  some  substances, 
that  can  exist  at  ordinary  temperature,  are  decomposed — 
that  is  to  say,  they  cannot  exist— at  high  temperatures.  This 
is,  in  fact,  true  of  many  of  the  substances  familiar  to  us. 
But  heat  not  only  decomposes  compounds ;  it  also,  if  not  too 
intense,  causes  elements  to  combine  to  form  compounds. 
In  the  laboratory  and  in  the  factory  heat  is  constantly 
being  employed  for  the  purpose  of  bringing  about,  or  aid- 
ing, chemical  action.  The  blast-furnace,  from  which  comes 
all  our  iron,  is  a  good  example.  The  object  in  view  is  the 
separation  of  the  metal,  iron,  from  its  ores.  The  ores  con- 
sist of  iron  in  combination  with  oxygen  and,  sometimes, 


314  MODERN  SCIENCE  READER 

other  things;  but  it  is  the  oxygen  that  gives  the  principal 
difficulty.  When  the  compound  of  iron  and  oxygen  is 
heated  with  something  that,  under  the  circumstances,  has 
the  power  to  combine  with  the  oxygen  and  escape  with  it 
in  the  form  of  a  gas,  the  iron  is  left  behind.  Charcoal  or 
coke  is  used  for  this  purpose.  At  high  temperatures,  these 
substances,  which  are  different  forms  of  the  element  car- 
bon, take  the  oxygen  from  the  iron,  and  the  metal  liberated 
sinks  to  the  bottom  of  the  furnace  in  the  molten  state,  while 
the  gaseous  compound  of  carbon  and  oxygen  passes  out  of 
the  top  of  the  furnace.  The  oxygen  changes  partners.  It 
is  to  be  observed  that  the  iron  ore  might  be  mixed  with  the 
charcoal,  and  the  mixture  allowed  to  stand  at  ordinary 
temperatures  for  any  length  of  time,  without  separation  of 
iron.  Heat  is  necessary,  and  a  good  deal  of  it,  to  cause  the 
charcoal  to  unite  with  the  oxygen  and  carry  it  off  into 
space. 

Heat  being  an  important  factor  in  chemical  acts,  the  ques- 
tion suggests  itself:  What  will  be  the  effect  upon  chemical 
processes  if  the  temperature  is  raised  much  above  the  range 
within  which  we  ordinarily  work?  And  at  the  same  time 
the  complementary  question  will  suggest  itself:  What  will 
be  the  effect  of  lowering  the  temperature  much  below  that 
at  which  we  ordinarily  work? 

EXTREMES  OF  TEMPERATURE 

Until  within  the  last  few  years  the  highest  temperatures 
attainable  were  reached  by  the  aid  of  the  so-called  compound 
blowpipe,  which  is  an  instrument  for  burning  hydrogen, 
or  some  other  combustible  gas,  in  oxygen  under  pressure. 
By  the  aid  of  this  instrument  platinum  was  melted  and, 
in  one  case,  silver  was  boiled.  But  now  the  introduction 
of  powerful  electric  currents  has  made  the  production 
of  much  higher  temperatures  possible,  and  marvelous  re- 
sults have  been  reached.  M.  Moissan,  of  Paris,  has  for 
some  time  been  engaged  in  studying  the  chemical  effects 
of  high  temperatures,  and  to  him  we  owe  almost  all  wo 


PROBLEMS   OF   CHEMISTRY  315 

know  of  chemistry  at  these  temperatures.  He  has  made 
use  of  a  simple  contrivance,  which  he  calls  an  electric 
furnace.  In  this  he  has  subjected  many  things  to  tem- 
peratures as  high  as  from  6,000  to  7,000  degrees  Fahren- 
heit. It  is  a  pity  that  Dante  could  not  have  taken  a  course 
in  chemistry  under  M.  Moissan.  These  temperatures,  not- 
withstanding their  great  height,  are  suggestive  of  the  lower 
regions.  This  work  has  opened  up  a  new  world  to  chemists, 
and  has  shown  them  that  there  are  many  unsolved  prob- 
lems to  be  found  here.  Things  that  unite  readily  at  ordi- 
nary high  temperatures  do  not  act  at  all  at  these  higher 
temperatures;  and  things  that  do  not  act  at  all  at  the 
former  act  vigorously  at  the  latter.  There  is  no  end  of 
what  may  be  learned  in  this  new  field. 

Just  as  it  is  desirable  to  know  how  things  act  upon  one 
another  at  high  temperatures,  so  it  is  equally  desirable  to 
know  how  they  act  at  low  temperatures.  Curiously  enough, 
work  in  this  direction  has  kept  pace  with  that  in  the  oppo- 
site direction,  referred  to  in  the  last  paragraph.  Within 
the  last  year  or  two,  the  attention  of  everybody  has  been 
directed  to  low  temperatures  by  the  interesting  work  that 
has  been  done  on  liquid  air.  It  is  well  known  that  air  can 
now  be  liquefied  on  the  large  scale,  and  that  liquid  air  is 
an  article  of  commerce.  This  brings  low  temperatures  to 
our  door,  for  it  is  only  necessary  to  expose  the  liquid  in  an 
open  vessel  to  produce  a  temperature  of  about  300  degrees 
below  zero,  Fahrenheit !  Then,  further,  Dewar  has  recently 
succeeded  in  liquefying  and,  indeed,  solidifying  hydrogen 
—a  much  more  difficult  feat  than  liquefying  air— and  with 
the  solid  thus  produced  he  has  reached  the  temperature 
432  degrees  below  zero,  Fahrenheit!  There  is  no  serious 
difficulty  then,  at  present,  in  studying  chemical  action  at 
temperatures  in  the  neighborhood  of  300  degrees  below 
zero.  The  first  results  are  not  reassuring.  Things  are  not 
very  lively  down  there,  to  say  the  least.  It  may  be  that 
all  chemical  action  ceases  below  a  certain  temperature,  but 
we  do  not,  as  yet,  know  enough  about  this  subject  to  justify 


316  MODERN  SCIENCE  READER 

us  in  speaking  with  confidence  about  it.  Countless  experi- 
ments yet  unborn  will  have  to  be  tried.  In  thinking  of  the 
possibilities,  we  are  confronted  with  what  appears  to  be  a 
paradox.  It  has  been  pointed  out  that  high  temperature, 
in  many  cases,  has  the  effect  of  decomposing  substances. 
This  shows  that  these  substances  are  more  stable  at  low 
temperatures  than  at  the  ordinary  temperatures.  In  other 
words,  if  heat  causes  the  constituents  to  separate,  cold 
might  apparently  cause  them  to  unite  more  firmly.  But, 
if  this  is  so,  why  do  not  substances  act  upon  each  other 
readily  at  low  temperatures?  It  may  be  that  the  constit- 
uents are  so  firmly  held  together  that  they  cannot  move 
about  among  one  another,  as  they  must  in  order  to  combine. 
The  water  that  is  frozen  in  a  glacier  does  not  act  like  water 
at  ordinary  temperatures.  It  is,  as  it  were,  chained  up 
and  prevented  from  obeying  the  laws  of  water. 

THE  GREAT  UNSOLVED 

In  what  I  have  thus  far  had  to  say,  I  have  kept  in  view 
certain  problems  which  do  not  necessarily  call  for  much 
speculation.  It  would,  however,  hardly  be  fair  to  leave 
the  speculative  side  of  chemistry  entirely  out  of  considera- 
tion. Sometimes  young  pupils  are  introduced  to  chemistry 
through  the  atom.  Only  very  young,  or  very  ignorant, 
persons  can  talk  with  confidence  about  atoms.  The  further 
one  goes  into  the  mysteries  of  chemistry,  the  more  myster- 
ious appears  the  atom.  In  fact,  the  atom  is  the  great  un- 
solved problem  of  chemistry.  But  this  is  subtle.  What  is 
an  atom  ?  Ah !  that  is  the  question.  It  has  been  a  favorite 
subject  of  thought  from  the  earliest  days.  Up  to  the  begin- 
ning of  the  ninteenth  century,  however,  it  was  nothing  but 
a  metaphysical  plaything.  The  wits  of  generations  of  phil- 
osophers have  -been  sharpened  by  efforts  to  decide  whether 
matter  is  infinitely  divisible  or  not.  Take  a  piece  of,  say, 
iron.  No  matter  what  its  size  may  be,  it  can  be  broken  up 
into  smaller  pieces;  and  each  of  the  pieces  thus  obtained 
can  be  still  further  subdivided.  Now,  how  far  can  this 


PROBLEMS   OF   CHEMISTRY  317 

process  of  subdivision  be  carried  ?  Is  there  any  limit  ?  The 
atomists  held  that,  after  a  time,  particles  would  be  reached 
so  small  that  they  could  not  be  made  smaller.  But  their 
opponents  said,  "No!  this  is  inconceivable.  Matter  must 
be  infinitely  divisible."  As  neither  side  could  prove  the 
other  wrong,  the  question  under  discussion  was  well  adapted 
to  the  purposes  of  controversy. 

The  atom  of  to-day  is  a  scientific  abstraction.  Many 
facts  have  been  brought  to  light  that  make  it  appear  cer- 
tain that  matter  is  not  continuous— is  not  capable  of  infinite 
subdivision.  Dalton,  the  Quaker  schoolmaster  of  Man- 
chester, was  the  first  one  to  bring  the  atom  down  to  the 
earth  and  make  it  a  useful  idea.  How  he  did  this  cannot 
be  shown  here.  Suffice  it  to  say,  the  atomic  theory  pro- 
posed by  Dalton  in  the  early  years  of  the  century  lives 
to-day,  and  is  stronger  than  it  has  ever  been,  notwithstand- 
ing the  efforts  that  have  been  made  to  show  that  it  is  built 
upon  sand.  It  has  been,  and  is  to-day,  an  extremely  useful 
theory.  Whether  it  will  always  continue  to  be  so  is  another 
question,  and  one  that  need  not  bother  us.  It  is  believed 
that  each  elementary  substance— that  is  to  say,  each  chem- 
ical element— consists  of  minute  particles  that  are  not 
broken  up  in  the  course  of  chemical  changes.  These  par- 
ticles that  remain  intact  are  the  atoms  of  chemistry.  Some 
such  theory  is  absolutely  necessary  to  account  for  the 
fundamental  laws  of  chemistry. 

Into  what  thin  air  we  enter,  when  we  begin  to  speak  of 
the  properties  of  the  individual  atom,  will  appear  when  it 
is  stated  that,  according  to  the  calculations  of  Lord  Kelvin, 
the  molecule  of  hydrogen,  which  is  at  least  twice  as  large 
as  its  atom,  is  of  such  size  that  it  would  take  50,000,000  of 
them  placed  in  a  row  to  occupy  an  inch !  To  be  sure,  most 
atoms  are  larger  than  those  of  hydrogen,  but  there  are  few 
so  large  that  it  would  not  be  necessary  to  have  about  a 
million  of  them  to  occupy  an  inch.  What  sense  is  there  in 
talking  about  such  things?  We  shall  never  be  able  to  see 
them,  or  to  prove  that  they  exist.  True,  but  the  conception 


318  MODERN  SCIENCE  READER 

of  the  atom  has  been  of  great  help  to  chemists,  and,  as  long 
as  it  continues  to  be  helpful,  it  will  be  clung  to. 

If  the  views  held  by  the  majority  of  chemists  are  true, 
the  science  of  chemistry  is  the  science  of  atoms.  The 
astronomer  has  to  deal  with  infinite  distances  and  the 
largest  masses  in  the  universe.  The  chemist,  on  the  other 
hand,  has  to  deal  with  the  shortest  distances  and  the  minut- 
est particles  of  matter.  The  astronomer  uses  the  telescope, 
but  there  is  no  microscope  that  can  carry  us  to  the  atom. 
The  astronomer  observes  points  of  light,  follows  their 
motions,  and  works  out  the  laws  that  govern  them.  The 
chemist  has  troubles  of  another  kind.  He  cannot  deal 
directly  with  single  atoms.  No  matter  how  small  a  quan- 
tity of  an  element  he  may  use  in  his  experiment,  he  has  to 
deal  with  a  large  number  of  atoms.  Every  time  he  per- 
forms an  experiment  millions  of  atoms  come  into  play.  He 
studies  his  substances  before  action  and  after  action.  New 
substances  are  formed,  and  he  concludes  that  the  atoms 
have  arranged  themselves  in  different  ways.  What  he 
knows  is  that  new  substances  with  new  properties  are 
formed.  He  knows  this  whether  atoms  are  realities  or  not, 
but  the  atom  helps  him  to  form  a  picture  of  what  probably 
takes  place  throughout  the  masses  with  which  he  is  dealing. 
The  atoms  are  as  far  removed  from  the  intellectual  gaze  of 
the  chemist  as  the  most  remote  stars  from  the  eye  of  the 
astronomer. 

Yet  the  chemist  talks  about  the  way  in  which  atoms  are 
combined  with  one  another ;  and  he  draws  figures,  and  con- 
structs models  to  show  it  all.  And  he  doesn't  do  this  for 
his  amusement,  but  because  he  is  helped  by  it.  He  talks 
in  the  language  of  chemistry,  as  the  mathematician  talks  in 
the  language  of  mathematics.  Some  day  he  will,  no  doubt, 
understand  the  language  better.  Probably  the  language 
itself  will  be  changed,  and  that  which  he  now  uses  will 
seem  like  the  prattle  of  an  infant. 

One  other  side  of  chemistry  must  be  turned  into  view 
before  I  can  close.  I  am  not  sure  that  I  can  make  myself 


PROBLEMS   OF   CHEMISTRY  319 

intelligible  in  what  I  still  have  to  say,  but  I  shall  try.  Thus 
far,  in  what  has  been  said  about  chemical  acts,  the  material 
side  has  been  kept  in  view.  The  relations  between  the  ele- 
ments; the  artificial  preparation  of  the  substances  that 
enter  into  the  composition  of  living  things;  the  changes  in 
the  composition  of  matter  at  high  and  at  low  temperatures ; 
and,  finally,  the  atom— these  are  the  subjects  dealt  with. 
But,  whenever  a  chemical  act  takes  place,  there  are  changes 
in  the  temperature  and  in  the  electrical  condition  of  the 
substances  involved,  in  addition  to  the  changes  in  compo- 
sition. It  is  while  in  action  that  chemical  substances  are 
most  interesting.  Generally  we  have  to  content  ourselves 
with  observations  before  and  after  an  act,  but  we  should 
learn  a  great  deal  more  about  the  nature  of  the  act,  if  we 
could  make  observations  while  it  is  in  progress.  We  should 
find  it  very  difficult,  if  not  impossible,  to  learn  the  law  of 
falling  bodies,  if  we  could  only  observe  bodies  before  and 
after  they  have  fallen ;  but  by  observing  them  in  the  act  of 
falling  we  can,  without  difficulty,  deduce  the  law 

LAWS  OF  CHEMICAL  CHANGE 

Generally  speaking,  chemical  acts  are  so  rapid  that  it  is 
impossible  to  make  observations  during  their  course.  Much 
progress  has  been  made  in  this  field  during  the  past  fifteen 
or  twenty  years,  and  some  of  the  great  laws  of  chemical 
action  have  been  discovered.  What  has  been  learned  is, 
however,  only  enough  to  whet  the  appetite  of  chemists.  'To 
illustrate  in  another  way  what  is  meant  by  making  observa- 
tions during  a  chemical  act,  let  us  take  the  case  of  gun- 
powder. This  usually  consists  of  charcoal,  sulphur,  and 
saltpeter.  A  spark  is  sufficient  to  cause  the  chemical  act 
that  is  accompanied  by  the  explosion.  We  can  collect 
everything  that  is  formed,  and  show  what  changes  in  com- 
position have  taken  place.  But  we  should  like  to  know 
something  about  the  act  itself,  and  yet,  plainly,  observa- 
tions during  the  act  cannot  be  numerous,  or  especially  in- 
structive. And  so  it  is  with  most  common  chemical  changes 


320  MODERN  SCIENCE  READER 

that  are  studied  in  the  laboratory.  We  get  only  snap-shots 
at  them.  If  we  could  only  get  a  series  of  pictures  at  short 
intervals,  we  might,  by  combining  these  afterward,  get 
some  idea  of  what  is  taking  place  during  the  act.  Fortun- 
ately, there  are  ways  of  controlling  certain  classes  of 
chemical  acts  and  reducing  their  speed,  so  that  observations 
can  be  made  during  their  progress;  and  much  has  been 
learned  in  this  way.  Here  is  a  great  field  for  further 
study,  and  it  presents  many  unsolved  problems. 

Finally,  a  few  words  about  water.  It  is  said  that  a  well- 
known  chemist  some  years  ago  made  a  bet  that  a  certain 
company  of  chemists  could  not  name  a  chemical  subject 
that  would  not,  in  turn,  suggest  to  him  a  profitable  chem- 
ical investigation.  Thereupon,  after  much  deliberation, 
the  challenged  company  sugges-ted  "water,"  on  the  assump- 
tion that  this  has  been  thoroughly  worked  over,  and  does 
not  present  unsolved  problems.  The  result  was  a  beautiful 
investigation  of  some  of  the  properties  of  water.  Every 
one  knows  that  water  is  the  most  abundant  substance  on 
the  earth.  It  also  plays  a  more  important  part  in  the 
changes  that  are  taking  place  on  the  earth  than  any  other 
substance.  We  are  only  beginning  to  learn  how  it  acts. 
That  it  dissolves  many  things  is  well  known,  but  let  us  not 
be  misled  because  this  phenomenon  is  so  common  and  so 
familiar.  Put  a  little  salt  in  water.  What  becomes  of  it? 
It  disappears.  There  is  no  solid  substance  in  the  vessel. 
We  may  bandy  phrases  as  we  please,  but  we  cannot  tell 
what  has  become  of  the  salt.  We  can  get  the  salt  out  of 
the  water  by  boiling  the  solution  and  letting  the  water  pass 
off  as  steam,  when  the  salt  will  be  left  behind.  As  we  put 
the  salt  in  and  take  it  out,  we  have  been  accustomed  until 
recently  to  think  of  the  salt  as  being  present  in  the  solution 
as  such.  One  of  the  most  important  advances  in  chemistry 
made  of  late  years  is  that  which  leads  to  the  conception 
that,  in  dilute  solutions  at  least,  there  is  little,  if  any,  salt 
present;  that,  in  some  way,  the  water  decomposes  it  into 
particles  highly  charged  with  electricity.  These  particles 


PROBLEMS   OF   CHEMISTRY  321 

are  called  ions.  This  idea  has  thrown  a  great  deal  of  light 
upon  important  problems  of  chemistry,  but  it  has  suggested 
many  new  ones  Some  substances— for  example,  sugar— 
do  not  act  like  salt  when  dissolved  in  water.  Why  this 
difference  ?  Then,  too,  some  liquids  which  are  good  solvents 
do  not  act  at  all  like  water.  What  is  it  in  water  that  dis- 
tinguishes it  from  most  other  liquids,  such  as  alcohol  and 
ether,  enabling  it  to  tear  many  substances  asunder?  These 
are  questions  that  are  now  very  much  to  the  front.  Rapid 
progress  is  being  made,  and  we  may  look  for  important 
discoveries  in  this  field  in  the  near  future.1 

1  This  article  was  first  published  in  1901.  The  reader  may  profit- 
ably consider  the  dates  of  discoveries  and  investigations  that  are 
given  in  this  book.  He  will  see  how  active  and  varied  have  been  the 
efforts  of  scientists,  in  recent  years  especially,  to  solve  the  problems 
of  Nature,  how  ingenious  have  been  their  methods  of  attack,  and  how 
with  the  solution  of  each  one  the  field  broadens  and  the  new  prob- 
lems become  more  difficult  and  more  fascinating. — ED. 


REGARDING  ADDITIONAL  READING 


THE  articles  contained  in  this  volume  first  appeared  in  the  follow- 
ing publications:  North  American  Review,  Iron  Age,  Journal  of  the 
Society  of  Arts,  Science,  Popular  Science  Monthly,  Edinburgh  Review, 
St.  Louis  Globe-Democrat,  Scientific  American  Supplement,  Harper's 
Monthly,  Engineering,  Prometheus,  American  Machinist,  Kosmos, 
Knowledge,  Scientific  News,  New  International  Encyclopaedia, 
McClure's  Magazine  and  Transactions  of  the  American  Electro- 
chemical Society. 

Those  who  wish  to  read  more  along  general  scientific  lines  will 
find  other  interesting  articles  by  referring  to  the  files  of  these  maga- 
zines. See  for  instance,  the  following:  "The  Eenaissance  of  the 
Alchemists, "  North  American  Review,  July,  1906.  "Chemistry  and 
the  World's  Food — the  Fixation  of  Nitrogen,"  Harper's  Monthly, 
April,  1906.  "The  Chemistry  of  the  Steam  Boiler/ '  Scientific 
American  Supplement,  December  11,  1909.  "Flower  Pigments," 
Scientific  American  Supplement,  April  10,  1909.  Messrs.  Munn  & 
Company,  361  Broadway,  New  York  City,  will  send  upon  request  a 
complete  index  to  the  Scientific  American  Supplement,  from  which 
readable  articles  may  be  found  upon  almost  any  subject  in  pure  and 
applied  science.  Individual  numbers  of  the  Supplement  may  be 
purchased  at  ten  cents  each.  By  referring  to  the  volume  of  the 
New  International  Encyclopaedia  entitled  "Courses  for  Eeading  and 
Study, "  one  will  find  references  to  topics  which  will  enable  him  to 
inform  himself  upon  almost  any  subject  whatsoever,  and  he  will 
also  find  directions  for  pursuing  an  interesting  and  systematic 
course  of  private  study.  At  the  end  of  the  encyclopaedic  articles 
there  is  given  the  names  of  books  which  treat  fully  the  topics  under 
consideration.  The  forthcoming  eleventh  edition  of  the  Encyclo- 
paedia Britannica  should  also  be  consulted. 

For  a  brief  though  broad  view  of  the  progress  of  Science,  one  may 
read  profitably  The  Progress  of  the  Century,  by  various  authors, 
and  The  Story  of  Nineteenth  Century  Science,  by  H.  S.  Williams, 
or  others  books  of  similar  import. 

It  is  true  that  interest  and  profit  come  through  reading  about 
matter  and  its  manifestations,  but  the  greatest  inspiration  comes 
through  reading  of  the  lives  and  work  of  men  whose  labors  have  built 

323 


ADDITIONAL  READING  323 

up  our  present  body  of  knowledge  or  applied  it  to  human  needs. 
Certain  considerations  prevented  such  from  being  included  in  this 
volume,  but  the  reader  is  referred  to  Thorpe's  Essays  in  Historical 
Chemistry  and  to  the  popular  sketches  that  have  appeared  in  many 
magazines;  a  number  of  these  have  been  reprinted  in  the  Scientific 
American  Supplement;  among  them  are  the  following:  Becquerel, 
Supplement  No.  1705;  Berthelot,  1328  and  1632;  Bessemer,  1161; 
Bunsen,  1241  and  1254;  Cavendish,  1554;  Crookes,  1672;  Men- 
deleeff,  1627;  Alfred  Nobel,  "His  Life  and  Will,"  1361  and  1463. 
The  New  International  Encyclopaedia  contains  sketches  of  the  work 
of  most  of  the  prominent  men,  among  whom  the  following  have  done 
much  in  the  field  of  Chemistry:  van  Helmont,  Becher,  Stahl,  Black, 
Priestley,  Cavendish,  Lavoisier,  Dalton,  Berzelius,  Davy,  Bertholet, 
Bergman,  Avogadro,  Gay-Lussac,  Mitscherlich,  Liebig,  Wohler,  Chev- 
reul,  Dumas,  Laurent,  Gerhardt,  Gmelin,  Sainte-Claire  Deville,  Can- 
nizzaro,  Graham,  Kolbe,  Bunsen,  Koscoe,  Berthelot,  Wurtz,  Hofmann, 
Eegnault,  Pasteur,  Baeyer,  Mendeleeff,  Schorlemmer,  Fischer,  van't 
Hoff,  Ostwald,  Nernst,  Arrhenius,  Crookes,  Dewar,  and  others. 


THE  following  pages  contain  a  list 
of  Macmillan  books  on  Chemistry 


A    LIST   OF    WORKS    ON    CHEMISTRY 

Published  by   The  Macmillan  Company 


RAMSAY.     Experimental  Proofs  of  Chemical  Theory  for  Beginners.     By 

WILLIAM  RAMSAY,  Ph.D.,  LL.D.,  Sc.D.,  F.R.S.    London,  1884.    Second  Edition, 
1893.    Reprinted,  1900,  1908.  Cloth,  18mo,  lltf  pages,  $  .60  net 

DONINGTON.  A  Class  Book  of  Chemistry.  By  G.  C.  DONINGTON,  City  of  Lon- 
don School.  Cloth,  12mo,  399  pages,  $  .90  net 

LENGFELD.  Inorganic  Chemical  Preparations.  By  FELIX  LENGFELD,  Assist- 
ant Professor  of  Inorganic  Chemistry  in  the  University  of  Chicago.  New  York, 
1899.  Reprinted  1905.  Cloth,  12mo,  57  pages,  $  .60  net 

BENEDICT.  Chemical  Lecture  Experiments.  By  FRANCIS  GANO  BENEDICT, 
Ph.D.  New  York,  1901.  Cloth,  12mo,  1*36  pages,  $2.00  net 

PERKIN  &  LEAN.  Introduction  to  the  Study  of  Chemistry.  By  W.  H.  PERKIN, 
Lr.,  Ph.D.,  F.R.S.,  and  BEVAN  LEAN,  D.Sc.,  B.A.  London,  1896.  Seventh  reprint, 
1906.  Cloth,  12mo,  SSkpages,  $  .75  net 

NERNST.  Theoretical  Chemistry  from  the  Standpoint  of  Avogadro's  Rule 
and  Thermodynamics.  By  Prof.  WALTER  NERNST,  Ph.D.,  of  the  University  of 
Gottingen.  Revised  in  accordance  with  the  fourth  German  edition.  London, 
1895.  Second  English  edition,  1904.  Cloth,  8vo,  771  pages,  $L50  net 

OSTWALD.  The  Scientific  Foundations  of  Analytical  Chemistry.  Treated 
in  an  elementary  manner.  By  WILHELM  OSTWALD.  Translated  with  the  author's 
sanction  by  George  M.  Gowan.  London,  1895.  Third  Edition,  1908. 

Cloth,  12mo,  2k7  pages,  $2. 00  net 

C1IKSNEAU.  Theoretical  Principles  of  the  Methods  of  Analytical  Chem- 
istry, based  upon  Chemical  Reactions.  By  M.  G.  CHESNEAU.  Authorized 
translation  by  A.  T.  Lincoln,  Ph.D.,  Assistant  Professor  of  Chemistry,  Rens- 
selaer  Polytechnic  Institute,  and  D.  H.  Carnahan,  Ph  D.,  Associate  Professor  of 
Romance  Languages,  University  of  Illinois.  New  York,  1910. 

Cloth,  8vo,  ISUpages,  $1.75  net 

JONES.  Practical  Inorganic  Chemistry  for  Advanced  Students.  By  CHAP- 
MAN JONES,  F.I.C.,  F.C.S.,  etc.  London,  1898.  Latest  reprint,  1906. 

Cloth,  12mo,  239  pages,  $  .60  net 

BASKERVILLE  &  CURTMAN.  Qualitative  Chemical  Analysis.  By  Professor 
CHARLES  BASKERVILLE  and  Dr.  L.  J.  CCRTMAN,  College  of  the  City  of  New  York. 
New  York,  1910.  Cloth,  8vo,  200  pages,  $l.kO  net 

XOYES.  A  Detailed  Course  of  Qualitative  Chemical  Analysis  of  Inor- 
ganic Substances.  With  Explanatory  Notes  by  ARTHUR  A.  NOTES,  Ph.D. 
New  York,  1899.  Cloth,  8vo,  89  pages,  $1.35  net 

MORGAN.  Qualitative  Analysis.  As  a  laboratory  basis  for  the  study  of  general 
inorganic  chemistry.  By  WILLIAM  CONGER  MORGAN,  Ph.D.,  Assistant  Professor 
of  Chemistry  in  the  University  of  California.  New  York,  1906.  Reprinted,  1907. 

Cloth,  8vo,  351  pages,  $1.90  net 

SCOTT.  An  Introduction  to  Chemical  Theory.  By  ALEXANDER  SCOTT.  Sec- 
ond Edition.  Cloth,  8vo,  272  pages,  $2.00  net 


A  LIST  OF  WORKS  ON  CHEMISTRY — Continued 


GATTERMAN.  The  Practical  Methods  of  Organic  Chemistry.  By  LUDWIG 
GATTERMAN,  Ph.D.  Translated  by  William  B.  Schober,  Ph.D.  The  second 
American  from  the  fourth  German  edition.  New  York,  1896,  1901.  Sixth  re- 
print, 1910.  Cloth,  Svo,  350  pages,  $1.60  net 

SHERMAN.  Methods  of  Organic  Analysis.  By  HENRY  C.  SHERMAN,  Ph.D.,  Ad- 
junct Professor  of  Analytical  Chemistry  in  Columbia  University.  New  York, 
1905.  Cloth,  Svo,  tU5  pages,  $1.75  net 

HAAS.  Laboratory  Notes  on  Organic  Chemistry  (for  Medical  Students). 
By  PAUL  HAAS,  St.  Thomas's  Hospital,  London.  Cloth,  12mo,  128  pages,  $  .80  net 

COHEN.    Theoretical  Organic   Chemistry.     By  JULIUS  B.  COHEN,  Ph.D.,  B.Sc. 

London,  1902.    Latest  reprint,  1907.  Cloth,  12mo,  578  pages,  $1.50  net 

COHEN.  Practical  Organic  Chemistry  for  Advanced  Students.  By  JULIUS 
B.  COHEN,  Ph.D.,  B.Sc.  London,  1900.  Second  Edition,  1908. 

Cloth,  12mo,  1*56  pages,  $  .80  net 

LASSAR- COHEN.  A  Laboratory  Manual  of  Organic  Chemistry.  A  com- 
pendium of  laboratory  methods  for  the  use  of  chemists,  physicians  and  pharma- 
cists. By  Dr.  LASSAR-COHEN.  Cloth,  Svo,  ltQ3  pages,  $2.25  net 

LACHMAN.  The  Spirit  of  Organic  Chemistry.  An  introduction  to  the  cur- 
rent literature  of  the  subject.  By  ARTHUR  LACHMAN,  Professor  of  Chemistry  in 
the  University  of  Oregon.  With  an  introduction  by  Paul  C.  Greer,  M.D.,  Ph.D., 
Professor  of  General  Chemistry  in  the  University  of  Michigan.  New  York,  1899. 
Second' reprint,  1909.  Cloth,  12mo,  229  pages,  $1.50  net 

MANN.  Chemistry  of  the  Proteids.  By  GUSTAV  MANN,  M.D.,  B.Sc.,  University 
Demonstrator  of  Physiology,  Oxford.  London,  1906. 

Cloth,  Svo,  606  pages,  $3.75  net 

LE  BLANC.  A  Text  Book  of  Electro-Chemistry.  By  MAX  LE  BLANC,  Univer- 
sity of  Leipzig.  Translated  by  Willis  R.  Whitney,  Ph.D.,  of  the  General  Electric 
Company,  and  John  W.  Brown,  Ph.D.,  of  the  National  Carbon  Company.  New 
York,  1907.  Reprinted,  1910.  Cloth,  Svo,  335  pages,  $2.60  net 

BLOUNT.  Practical  Electro-Chemistry.  By  BERTRAM  BLOUNT,  F.L.C.,  Assoc. 
Inst.  C.E.  London,  1901.  Second  Edition.  Revised,  1906. 

Cloth,  Svo,  S9k  pages,  $3.25  net 

THOMPSON.  Applied  Electro-Chemistry.  By  M.  DEKAY  THOMPSON,  of  the 
Massachusetts  Institute  of  Technology.  New  York,  1911. 

Cloth,  Svo,  329  pages,  $2.10  net 

NEUMANN.     The  Theory  and  Practice  of  Electrolytic  Methods  of  Analysis. 

By  Dr.  BERNHARD  NEUMANN.    Translated  by  John  B.  C.  Kerslaw,  F.I.C.    London, 
1878.  Cloth,  Svo,  25k  pages,  $3.00  net 


A  LIST  OF  WORKS  ON  CHEMISTRY — Continued 


BARTHEL.    Methods  used  in  the  Examination  of  Milk  and  Dairy  Products. 

By  Dr.  CHR.  BARTHEL,  Stockholm.    Translation  by  W.  Goodwin,  M.Sc.,  Ph.D. 
London,  1910.  Cloth,  Svo,  260  pages,  $1.90  net 

SNYDER.  Human  Foods  and  their  Nutritive  Value.  By  HARRY  SNYDER,  B.S., 
Professor  of  Agricultural  Chemistry,  University  of  Minnesota,  and  Chemist  of 
the  Minnesota  Experiment  Station.  New  York,  1909. 

Cloth,  12mo,  862pages,  $1.25  net 

ROLFE.  The  Polariscope  in  the  Chemical  Laboratory.  An  introduction  to 
polarimetry  and  related  methods.  By  GEORGE  WILLIAM  ROLFE,  A.M.,  Instruct- 
or in  Sugar  Analysis  in  the  Massachusetts  Institute  of  Technology.  New  York, 
1905.  Cloth,  12mo,  320  pages,  $1.90  net 

YOUNG.  Fractional  Distillation.  By  SIDNEY  YOUNG,  D.Sc.,  F.R.S.,  Professor  of 
Chemistry  in  University  College,  Bristol.  London,  1903. 

Cloth,  12mo,  28k  pages,  $2.60  net 

MELDOLA.  The  Chemistry  of  Photography.  By  RAPHAEL  MELDOLA,  F.R.S., 
etc.  London,  1899.  Latest  reprint,  1901.  Cloth,  12mo,  382  pages,  $2.00  net 

DERR.  Photography  for  Students  of  Physics  and  Chemistry.  By  Louis 
DERR,  M.A.,  S.B.,  Associate  Professor  of  Physics  in  the  Massachusetts  Institute 
of  Technology.  New  York,  1906.  Reprinted  1909.  Cloth,  12mo,  Zkl  pages,  $l./tO  net 

FRAPS.  Principles  of  Dyeing.  By  G.  S.  FRAPS,  Ph.D.,  Assistant  Professor  of 
Chemistry,  North  Carolina  College  of  Agriculture  and  Mechanic  Arts.  New 
York,  1903.  Cloth,  12mo,  270  pages,  $1.60  net 

SCHULTZ  &  JULIUS.  A  Systematic  Survey  of  the  Organic  Colouring  Mat- 
ters. Founded  on  the  German  of  Drs.  G.  SCHULTZ  and  P.  JULIUS.  Revised 
throughout  and  greatly  enlarged  by  Arthur  G.  Green,  F.I.C.,  F.C.S.  London. 

Cloth,  8vo,  200  pages,  $7.00  net 

LEWKOWITSCH.  Chemical  Technology  and  Analysis  of  Oils,  Fats  and 
Waxes.  By  Dr.  J.  LEWKOWITSCH,  M.A.,  F.I.C.,  Consulting  Chemist  to  the  city 
and  guilds  of  London  Institute.  Fourth  Edition.  Entirely  rewritten  and  en- 
larged. 3  vols.  London,  1909. 

Cloth,  Svo,  Vol.  1 51^  pages,    Vol.  II 812  pages.    Vol.  Ill  k06  pages,  $15.00  net 

LEWKOWITSCH.  Laboratory  Companion  to  Fats  and  Oils  Industries.  By 
Dr.  J.  LEWKOWITSCH,  M.A.,  F.I.C.  London,  1900.  Cloth,  Svo,  197  pages,  $1.90  net 

GUTTMAN.  Manufacture  of  Explosives.  By  OSCAR  GUTTMAN,  Assoc.  M.  Inst. 
C.E.,  F.I.C.  In  two  volumes.  London,  1895. 

Cloth,  Svo,  Vol.  I  3k8  pages.  Vol.  II IM  pages,  the  set,  $9.00  net 
HERMAN.     Chemistry  of  Food  and  Nutrition.     By  HENRY  C.  SHERMAN,  Ph.D., 
Professor  of  Organic  Analysis  in  Columbia  University. 

Cloth,  12mo,  855  pages,  $1.50  net 


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